Welcome to COPhoneLookup.com – Colorado’s #1 Reverse Phone Lookup & Area Code Directory
- Complete List of Colorado Area Codes & the Cities They Cover — Explore our full list of Colorado area codes and see which cities they serve, including Denver, Colorado Springs, Aurora, Fort Collins, Lakewood, and Boulder. Instantly match a Colorado area code to its city, county, or region using our Colorado reverse phone lookup tool.
- Colorado’s Largest Cities – Populations, Area Codes & Common Prefix Numbers — Discover which Colorado phone prefixes are linked to the 303, 719, 720, 970, and 983 area codes for major cities like Denver (Denver County), Colorado Springs (El Paso County), Aurora (Arapahoe County), Fort Collins (Larimer County), Lakewood (Jefferson County), and Thornton (Adams County). This makes it easy to determine where a call might be coming from before running a complete Colorado reverse phone search.
- Colorado’s Largest Counties – Populations, Cities, Area Codes & Common Prefix Numbers — See how the 303, 719, 720, 970, and 983 area codes are assigned across Denver County, El Paso County, Arapahoe County, Jefferson County, Adams County, Douglas County, Boulder County, Larimer County, and Weld County. Find the most common prefix numbers for each county so you can verify if a Colorado phone number is truly local.
- Colorado Reverse Phone Lookup — Got an unexpected call or text from a 303, 719, 720, 970, or 983 number? Our Colorado reverse phone lookup instantly reveals the caller’s name, location, phone carrier, and any available public details.
- Free Colorado Phone Lookup Guide — Learn step-by-step how to search for Colorado phone numbers, spot Colorado spam calls, block Colorado robocalls, and identify spoofed Colorado area codes — without paying a dime.
- Colorado Phone Lookup FAQ — Get clear answers to your most common questions about Colorado phone numbers, reverse phone lookups, Colorado area codes, Colorado prefix numbers, and how to confirm the real origin of a call.
Want to know exactly who’s calling from a Colorado phone number?
COPhoneLookup.com is your go-to Colorado reverse phone search tool and area code directory. In just seconds, you can run a free reverse phone lookup Colorado State to uncover the caller’s name, location, phone carrier, Colorado prefix code, and even public records tied to the number. Whether you need a Colorado cell phone lookup, a landline search, or a lookup of a CO phone number owner, our service makes it quick and simple.
If the number begins with the 303 area code (Denver, Boulder, Westminster, Arvada)… the 719 area code (Colorado Springs, Pueblo, Fountain)… the 720 area code (Aurora, Centennial, Thornton, Longmont)… the 970 area code (Fort Collins, Loveland, Greeley, Grand Junction)… or the 983 area code (overlay for the 303/720 region) — our Colorado reverse phone lookup will give you accurate results right away. Many people use it to confirm if a call is really local, check Who Called Me Colorado, or spot spoofed numbers pretending to be from familiar Colorado area codes.
With COPhoneLookup.com, you can:
- Search Colorado phone numbers by combining area code and prefix for precise results.
- Find out who owns a number with our Colorado number owner finder.
- Search Colorado phone numbers by name to reconnect with someone.
- Run a Colorado spam call lookup or Colorado robocall lookup to stop nuisance calls.
- Perform specialized lookups like CO business number reverse searches or Colorado jail inmate phone lookups.
- Use the Colorado phone directory to get complete caller profiles, addresses, and carrier details.
Keep reading for our Colorado area code chart by city and county, full Colorado prefix listings, and expert tips for running an effective Colorado reverse phone search. No matter if it’s the 303, 719, 720, 970, or 983 area code, COPhoneLookup.com helps you identify any Colorado caller — quickly, accurately, and without the stress.
Colorado Area Codes – 303, 719, 720, 970, 983: What They Mean & How to Trace Any Colorado Phone Number
Every Colorado phone number begins with a three-digit Colorado area code — the part of the number that indicates where the call was originally registered. These 303, 719, 720, 970, and 983 area codes aren’t just random digits; they’re your first clue in identifying the caller’s possible location.
Whether you get a call from Denver in the 303 area code, Colorado Springs in the 719 area code, Aurora in the 720 area code, Fort Collins in the 970 area code, or parts of the Denver metro in the 983 area code, knowing the Colorado area code helps you start your search with confidence.
Colorado’s Five Active Area Codes
- 303 Area Code – Covers Denver, Boulder, Arvada, Westminster, Lakewood, and surrounding metro cities. A 303 reverse lookup or 303 phone number lookup can confirm if a call is genuinely from the Denver area using our Denver phone number lookup tool.
- 719 Area Code – Serves Colorado Springs, Pueblo, Fountain, and other cities in southern Colorado. A 719 reverse lookup or 719 phone number lookup helps verify if a number is truly local or a spoofed call.
- 720 Area Code – Overlays much of the 303 area code region, serving Aurora, Thornton, Centennial, Broomfield, and parts of the Denver metro. Many people use a 720 reverse lookup or 720 phone number lookup to trace calls in this high-growth area.
- 970 Area Code – Assigned to Fort Collins, Loveland, Greeley, Grand Junction, Steamboat Springs, and other northern and western Colorado communities. Running a 970 reverse lookup or 970 phone number lookup can quickly match a call to its possible origin.
- 983 Area Code – A newer overlay for the 303/720 region, covering much of the Denver metro. A 983 reverse lookup or 983 phone number lookup confirms whether the call is genuine or spoofed.
Why Prefix Numbers Matter
While Colorado area codes narrow down the region, they don’t always pinpoint the exact location. The prefix numbers — the three digits after the area code — can identify the specific city, town, or local exchange where the phone number was first assigned.
At COPhoneLookup.com, you can combine Colorado area codes with Colorado prefix numbers to trace any Colorado phone number. Our Colorado reverse phone lookup tool can reveal the caller’s name, business, address history, linked social media profiles, phone type (mobile, landline, or VoIP), carrier details, and matches from the Colorado phone directory.
Protecting Against Spoofed Calls
Scammers often spoof numbers to appear local — a 303 area code might look like it’s from Denver, or a 719 area code might seem like it’s from Colorado Springs, when it’s not. Our tools verify whether the number’s location is genuine or fake, helping you avoid scams.
You Can Use COPhoneLookup.com For:
- Checking a suspicious number with a 303 phone number lookup or 719 phone number lookup.
- Searching the Colorado phone directory for a name or address.
- Looking up Colorado prefix numbers for a specific area.
- Using a Denver phone number lookup, Colorado Springs phone number lookup, Fort Collins phone number lookup, or Boulder phone number lookup to confirm a caller.
With complete coverage of all Colorado area codes — 303, 719, 720, 970, and 983 — plus every prefix in the state, COPhoneLookup.com gives you fast, accurate, and private results so you always know exactly who’s trying to reach you.
Complete List of Colorado Area Codes & the Cities They Cover
If you’ve received a call or text from a Colorado phone number you don’t recognize, the area code is your first clue to where it may have originated. The first three digits — whether it’s the 303 area code for Denver and Boulder, the 719 area code for Colorado Springs and Pueblo, the 720 area code for Aurora and Thornton, the 970 area code for Fort Collins and Grand Junction, or the 983 area code serving parts of the Denver metro — can help you quickly narrow down the call’s possible location.
Colorado currently has five active area codes: 303, 719, 720, 970, and 983. While number portability means people can keep their numbers even after moving, many Colorado area code and prefix number combinations (the first six digits of a phone number) still provide valuable insight into where the call was first registered.
This guide provides a Colorado area code list by city so you can quickly match a phone number to its most likely origin:
- 303 Reverse Lookup – Covers Denver, Boulder, Arvada, Westminster, Lakewood, and other central Colorado metro areas. Use our Denver phone number lookup to check unfamiliar calls from the 303 area code.
- 719 Reverse Lookup – Serves Colorado Springs, Pueblo, Fountain, and surrounding southern Colorado communities. A 719 phone number lookup helps verify if a number is truly from the Colorado Springs or Pueblo area.
- 720 Reverse Lookup – Overlays much of the 303 area code region, serving Aurora, Thornton, Centennial, Broomfield, and other cities in the Denver metro. Many people use a 720 phone number lookup to trace calls from this fast-growing region.
- 970 Reverse Lookup – Assigned to Fort Collins, Loveland, Greeley, Grand Junction, Steamboat Springs, and other northern and western Colorado areas. Running a 970 phone number lookup can match a call to its likely origin.
- 983 Reverse Lookup – A newer overlay for the 303/720 region, covering much of the Denver metro. A 983 phone number lookup can confirm whether the call is genuine or spoofed.
Our Colorado reverse phone lookup goes beyond simply matching an area code. By including the Colorado prefix numbers in your search, you can uncover the caller’s name, address, phone carrier, linked social media accounts, and Colorado phone directory matches. This is the easiest way to confirm if a Colorado number is genuine or a spoofed call designed to look local.
Whether you want to:
- Verify a suspicious Colorado phone number.
- Identify the true source of a missed call.
- Learn more about Colorado area codes and prefix numbers.
- Search the Colorado phone directory for contact details.
You can find answers here. Scroll down to view the full Colorado area code list by city and start your search with confidence.
| Area Code | Cities & Towns |
| 303 Area Code | Acres Green, Aetna Estates, Allenspark, Altona, Applewood, Aristocrat Ranchettes, Arvada, Aspen Park, Aurora, Bark Ranch, Bennett, Berkley, Black Hawk, Bonanza Mountain Estates, Boulder, Bow Mar, Brick Center, Brighton, Broomfield, Byers, Castle Pines, Castle Pines North, Castle Rock, Centennial, Central City, Cherry Creek, Cherry Hills Village, Coal Creek, Columbine, Columbine Valley, Comanche Creek, Commerce City, Crisman, Dacono, Dakota Ridge, Deer Trail, Denver, Derby, Dove Valley, Downieville-Lawson-Dumont, East Pleasant View, Edgewater, Elbert, Eldora, Eldorado Springs, Elizabeth, Empire, Englewood, Erie, Evergreen, Fairmount, Federal Heights, Firestone, Floyd Hill, Fort Lupton, Foxfield, Franktown, Frederick, Genesee, Georgetown, Glendale, Glendale, Golden, Gold Hill, Grand View Estates, Greenwood Village, Gunbarrel, Hidden Lake, Highlands Ranch, Holly Hills, Hudson, Idaho Springs, Idledale, Indian Hills, Inverness, Jamestown, Keenesburg, Ken Caryl, Kiowa, Kittredge, Lafayette, Lakeside, Lakewood, Larkspur, Lazy Acres, Leyner, Littleton, Lochbuie, Lone Tree, Longmont, Louisville, Louviers, Lyons, Meridian, Morrison, Mountain Meadows, Mountain View, Nederland, Niwot, Northglenn, North Washington, Paragon Estates, Parker, Peoria, Perry Park, Pine Brook Hill, Ponderosa Park, Rollinsville, Roxborough Park, St. Ann Highlands, St. Mary's, Sedalia, Seven Hills, Shaw Heights, Sheridan, Sherrelwood, Silver Plume, Stonegate, Strasburg, Sugarloaf, Sunshine, Superior, Tall Timber, The Pinery, Thornton, Todd Creek, Twin Lakes, Upper Bear Creek, Valmont, Ward, Watkins, Welby, Westcreek, Westminster, West Pleasant View, Wheat Ridge. |
| 719 Area Code | Aguilar, Air Force Academy, Alamosa, Alamosa East, Alma, Alpine, Antonito, Arriba, Avondale, Bethune, Beulah Valley, Black Forest, Blanca, Blende, Bonanza, Boone, Brandon, Branson, Brookside, Buena Vista, Burlington, Calhan, Campo, Ca, Capulin, Cascade-Chipita Park, Center, Cheraw, Cheyenne Wells, Cimarron Hills, City of Creede, Coal Creek, Coaldale, Cokedale, Colorado City, Colorado Springs, Conejos, Cotopaxi, Crestone, Cripple Creek, Crowley, Del Norte, Divide, Eads, Ellicott, El Moro, Fairplay, Flagler, Florence, Florissant, Fort Carson, Fort Garland, Fountain, Fowler, Garfield, Genoa, Gerrard, Gleneagle, Goldfield, Granada, Green Mountain Falls, Guffey, Hartman, Hasty, Haswell, Hoehne, Holly, Hooper, Howard, Hugo, Jansen, Johnson Village, Kim, Kit Carson, La Jara, La Junta, La Junta Gardens, Lamar, Las Animas, La Veta, Leadville, Leadville North, Limon, Lincoln Park, Lynn, Manassa, Manitou Springs, Manzanola, Maysville, Midland, Moffat, Monte Vista, Monument, North La Junta, Olney Springs, Ordway, Palmer Lake, Penrose, Peyton, Poncha Springs, Pritchett, Pueblo, Pueblo West, Ramah, Rock Creek Park, Rockvale, Rocky Ford, Romeo, Rye, Saguache, Salida, Salt Creek, San Acacio, Sanford, San Luis, Security-Widefield, Segundo, Sheridan Lake, Silver Cliff, Simla, Smeltertown, South Fork, Springfield, Starkville, Stonewall Gap, Stratmoor, Stratton, Sugar City, Swink, Towner, Trinidad, Twin Lakes, Two Buttes, Valdez, Victor, Vilas, Vineland, Vona, Walsenburg, Walsh, Westcliffe, Weston, Wiley, Williamsburg, Woodland Park, Woodmoor. |
| 720 Area Code | Area code 720 is an overlay for the 303 area code in central Colorado, covering much of the Denver metropolitan area. It was introduced to meet the growing demand for phone numbers in fast-expanding cities like Aurora, Thornton, Centennial, and Broomfield. Because 720 shares the same coverage as its overlay partner 303, a 720 reverse lookup or 720 phone number lookup will show the same cities and counties served by 303, making it easy to identify unknown callers or confirm if a number is truly local. |
| 970 Area Code | Akron, Amherst, Arboles, Aspen, Atwood, Ault, Avon, Basalt, Battlement Mesa, Bayfield, Berthoud, Blue River, Blue Sky, Breckenridge, Brush, Carbondale, Cathedral, Catherine, Cattle Creek, Cedaredge, Chacra, Clifton, Collbran, Colona, Copper Mountain, Cortez, Craig, Crawford, Crested Butte, Crook, De Beque, Delta, Dillon, Dinosaur, Dolores, Dotsero, Dove Creek, Durango, Eagle, Eaton, Eckley, Edwards, El Jebel, Estes Park, Evans, Fleming, Fort Collins, Fort Morgan, Fraser, Frisco, Fruita, Fruitvale, Fulford, Garden City, Gilcrest, Glenwood Springs, Granby, Grand Junction, Grand Lake, Greeley, Grover, Gunnison, Gypsum, Haxtun, Hayden, Heeney, Hillrose, Holyoke, Hotchkiss, Hot Sulphur Springs, Idalia, Ignacio, Iliff, Jackson Lake, Joes, Johnstown, Julesburg, Kersey, Keystone, Kirk, Kremmling, Laird, Lake City, Laporte, La Salle, Lewis, Loghill Village, Log Lane Village, Loma, Loveland, McCoy, Mancos, Marble, Maybell, Mead, Meeker, Merino, Milliken, Minturn, Montezuma, Montrose, Morgan Heights, Mountain Village, Mount Crested Butte, Mulford, Naturita, New Castle, No Name, Norrie, Norwood, Nucla, Nunn, Oak Creek, Olathe, Ophir, Orchard, Orchard City, Orchard Mesa, Otis, Ouray, Ovid, Padroni, Pagosa Springs, Palisade, Paoli, Paonia, Parachute, Parshall, Peetz, Phippsburg, Piedra, Pierce, Pitkin, Platteville, Portland, Rangely, Raymer (New Raymer), Red Cliff, Red Feather Lakes, Redlands, Redstone, Redvale, Rico, Ridgway, Rifle, Saddle Ridge, Sawpit, Sedgwick, Seibert, Severance, Silt, Silverthorne, Silverton, Snowmass Village, Snyder, Southern Ute, Steamboat Springs, Sterling, Tabernash, Telluride, Timnath, Towaoc, Trail Side, Vail, Vernon, Walden, Weldona, Wellington, Wiggins, Windsor, Winter Park, Wolcott, Woody Creek, Wray, Yampa, Yuma. |
| 983 Area Code | Area code 983 is an overlay for the 303 and 720 area codes in central Colorado, covering much of the Denver metropolitan area. It was introduced to address the growing demand for phone numbers in rapidly expanding cities like Denver, Boulder, Westminster, and Lakewood. Because 983 shares the same coverage as its overlay partners 303 and 720, a 983 reverse lookup or 983 phone number lookup will show the same cities and counties served by those area codes, making it easy to identify unknown callers or confirm if a number is truly local. |
Colorado’s Largest Cities – Populations, Area Codes & Common Prefix Numbers
When you’re trying to figure out where a Colorado phone number originated, the first step is to look at its area code and the next three digits, known as the prefix number. These two parts of the number can reveal a lot about the caller’s possible location — often before you even run a Colorado reverse phone lookup. By combining area code and prefix data with population information, you can quickly narrow down whether the number is tied to a major metro area like Denver, Colorado Springs, Aurora, Fort Collins, Lakewood, or Thornton, or if it’s coming from a smaller city or rural community in Colorado.
For example, calls from the 303 area code typically originate from Denver, Boulder, Arvada, Westminster, Lakewood, and other nearby communities in central Colorado. The 719 area code is associated with Colorado Springs, Pueblo, Fountain, and many cities in southern Colorado. The 720 area code is an overlay for the 303 region, covering Aurora, Centennial, Thornton, Broomfield, and parts of the Denver metro. The 970 area code is common for Fort Collins, Loveland, Greeley, Grand Junction, Steamboat Springs, and other northern and western Colorado areas. The 983 area code is a newer overlay for the 303/720 region, serving much of the Denver metro as well.
Looking at the prefix number — the three digits after the area code — can narrow things down even further. Certain prefixes are unique to specific neighborhoods, towns, or local exchanges. This extra detail is useful if you’re doing a Colorado cell phone lookup, landline lookup, or trying to verify an unfamiliar caller with a Who Called Me Colorado search.
Understanding these patterns can help you:
- Verify a caller’s location before you answer the phone.
- Recognize and identify Colorado numbers you’ve never seen before.
- Investigate suspicious texts, spam calls, robocalls, or telemarketing from Colorado area codes.
- Use the Colorado phone directory or a Colorado reverse phone search tool to uncover the name, address, carrier, and public records linked to the number.
In the next section, you’ll find a detailed reference for Colorado’s largest cities, their assigned area codes, and the most common prefix numbers in each location. This guide is designed to help you perform accurate Colorado phone number lookups, verify Colorado area codes, and determine whether a call is genuinely local or potentially spoofed.
| City Name | Facts |
| Denver | Denver is Colorado’s largest city and the state capital, serving as the political, economic, and cultural hub of the Rocky Mountain region. Known for its thriving downtown, sports teams, breweries, and easy access to the mountains, Denver draws residents from across the U.S. and tourists from around the world. Major industries include technology, finance, healthcare, tourism, and energy. Most Denver calls display the 303 area code, while newer numbers may use the 720 or 983 overlays. Many locals and businesses rely on a Denver phone number lookup, 303 reverse lookup, or free Colorado reverse phone search to identify unknown calls. Because Denver has a high rate of relocation and temporary residents, numbers from other states are also common, making a lookup tool essential for verifying callers. Population: ~715,000 Area Codes: 303, 720, 983 Common Prefixes: 303-295, 303-298, 303-322, 303-333, 303-355, 303-377, 303-394, 720-440, 720-465, 720-515, 983-210 |
| Colorado Springs | Colorado Springs lies at the base of Pikes Peak and is known for its outdoor beauty, military presence, and family-friendly communities. It’s home to major installations like Fort Carson, Peterson Space Force Base, and the U.S. Air Force Academy. The city is also a growing hub for cybersecurity, defense contracting, and tourism. Nearly all local lines use the 719 area code, and a Colorado Springs phone number lookup or 719 reverse lookup is the fastest way to verify if a call is truly local. Many incoming calls come from military families, temporary duty assignments, or telemarketing targeting military households, so a free Colorado phone lookup can be helpful for avoiding scams. Population: ~486,000 Area Code: 719 Common Prefixes: 719-210, 719-219, 719-260, 719-282, 719-314, 719-352, 719-390, 719-473, 719-599, 719-660 |
| Aurora | Aurora is one of Colorado’s most diverse and rapidly growing cities, located just east of Denver. It’s known for its medical district, including the University of Colorado Anschutz Medical Campus, and large parks such as Cherry Creek State Park. Aurora uses the 303, 720, and 983 area codes. A Aurora CO phone number lookup or free 303 reverse lookup can confirm the caller’s origin, which is especially useful given the city’s mix of residential, commercial, and military populations. Large apartment complexes and transient residents mean phone numbers may not always align perfectly with location, making prefix searches more valuable. Population: ~398,000 Area Codes: 303, 720, 983 Common Prefixes: 303-326, 303-341, 303-344, 720-272, 720-317, 720-400, 983-215, 983-234 |
| Fort Collins | Fort Collins is a thriving college town and tech hub in northern Colorado, home to Colorado State University and a nationally recognized craft beer scene. The city is known for its bike-friendly streets, outdoor recreation, and proximity to Rocky Mountain National Park. Most local numbers use the 970 area code, and a Fort Collins phone number lookup or free 970 reverse lookup can quickly identify calls from within the metro or nearby towns like Loveland and Windsor. Population: ~170,000 Area Code: 970 Common Prefixes: 970-217, 970-221, 970-225, 970-267, 970-372, 970-481, 970-568, 970-690 |
| Lakewood | Lakewood, just west of Denver, offers a suburban lifestyle with quick access to downtown and the mountains. It’s home to Colorado Mills mall, multiple parks, and cultural venues like the Lakewood Cultural Center. Residents and businesses share the 303, 720, and 983 area codes. A Lakewood CO phone lookup is helpful for confirming calls from Jefferson County, where many scammers try to spoof local numbers. Population: ~157,000 Area Codes: 303, 720, 983 Common Prefixes: 303-232, 303-238, 303-239, 720-217, 720-260, 720-389, 983-220 |
| Thornton | Thornton is a fast-growing community in Adams County, part of Denver’s north metro area. It’s known for new housing developments, parks, and convenient access to downtown Denver. Thornton uses the 303, 720, and 983 area codes. A Thornton phone number lookup or free Colorado reverse lookup can confirm if calls are from the north suburbs or from spoofed telemarketing lines. Population: ~147,000 Area Codes: 303, 720, 983 Common Prefixes: 303-255, 303-280, 303-287, 720-322, 720-399, 983-230 |
| Arvada | Arvada blends historic charm with modern amenities, offering Olde Town Arvada’s shops and restaurants alongside easy access to both Denver and Boulder. It uses the 303, 720, and 983 area codes. Residents often run a Arvada CO phone number lookup to verify local business calls. Population: ~122,000 Area Codes: 303, 720, 983 Common Prefixes: 303-420, 303-431, 303-467, 720-242, 720-316, 983-240 |
| Westminster | Westminster spans both Jefferson and Adams counties and features parks, shopping districts, and quick access to Denver and Boulder. It uses the 303, 720, and 983 area codes. Population: ~116,000 Area Codes: 303, 720, 983 Common Prefixes: 303-412, 303-427, 303-469, 720-214, 720-427, 983-250 |
| Pueblo | Pueblo is a historic city in southern Colorado with strong steel industry roots and a growing arts scene. Known for the annual Chile & Frijoles Festival, Pueblo uses the 719 area code exclusively. A Pueblo CO phone number lookup is often used to verify local small business calls. Population: ~112,000 Area Code: 719 Common Prefixes: 719-225, 719-250, 719-281, 719-543, 719-565, 719-671 |
| Centennial | Centennial is a suburban city in Arapahoe County with top-rated schools, retail centers, and residential neighborhoods. It uses the 303, 720, and 983 area codes. Population: ~107,000 Area Codes: 303, 720, 983 Common Prefixes: 303-220, 303-754, 720-200, 720-270, 983-260 |
| Boulder | Boulder is a scenic city at the base of the Flatirons, known for outdoor recreation, natural foods companies, and the University of Colorado. It uses the 303, 720, and 983 area codes. A Boulder CO phone lookup can confirm calls from both residential lines and local businesses. Population: ~104,000 Area Codes: 303, 720, 983 Common Prefixes: 303-441, 303-449, 303-492, 720-306, 720-564, 983-270 |
| Greeley | Greeley is an agricultural and educational center in northern Colorado, home to the University of Northern Colorado. Most local calls use the 970 area code. Population: ~110,000 Area Code: 970 Common Prefixes: 970-302, 970-330, 970-352, 970-405, 970-576, 970-673 |
Colorado’s Largest Counties: Populations, Cities, Area Codes & Common Prefix Numbers
If you’re trying to figure out where a Colorado phone number really comes from, you’ll want to go beyond just the city name on caller ID. Many Colorado counties are covered by multiple Colorado area codes, and understanding how area codes and prefix numbers (NPA-NXX) are assigned at the county level can help you pinpoint the true origin of a call.
This Colorado county phone lookup guide connects unfamiliar numbers to their most likely source — whether it’s Denver County, El Paso County, Arapahoe County, Jefferson County, or Boulder County. Even if a call appears local, combining the area code with the next three digits (prefix) can reveal whether it’s truly from Colorado or a spoofed number made to look local.
While city-based lookups focus on places like Denver, Colorado Springs, and Aurora, this reverse phone lookup by county takes a wider approach, giving you:
- Active Colorado area codes for each county, including the 303 area code, 719 area code, 720 area code, 970 area code, and 983 area code.
- Common prefix numbers tied to carriers in that region.
- The major cities and towns linked to those number ranges.
This county-level resource is especially helpful if you want to:
- Run a Colorado reverse phone lookup to confirm a caller’s name, address, and carrier.
- Use a Denver phone number lookup, Colorado Springs phone lookup, or Boulder phone lookup to verify an unknown caller.
- Identify Colorado spam calls or robocalls using local area codes to trick recipients.
- Double-check whether a call originates in Colorado or from another state.
- Pinpoint the most likely location of a Colorado phone number before deciding whether to answer or block it.
By matching Colorado area code data with associated prefix patterns, you can quickly see whether a number is genuinely local, possibly suspicious, or safe to call back. This guide covers every county served by the 303 reverse lookup, 719 reverse lookup, 720 reverse lookup, 970 reverse lookup, and 983 reverse lookup, making it one of the most complete Colorado phone directory resources for identifying exactly who’s calling.
| County Name | Facts |
| Denver County | Denver County is Colorado’s most populous urban hub, home to the state capital, Denver, and serving as a major center for government, finance, healthcare, and tourism. Phone numbers here are primarily in the 303 and 720 area codes, with the newer 983 overlay serving additional lines. Prefix numbers make it easy to narrow down the specific neighborhood or business district. A Denver phone number lookup or 303 reverse lookup is a quick way to confirm whether a call is local. Population: ~717,000 Major Cities: Denver Area Codes: 303, 720, 983 Common Prefixes: 303-295, 303-321, 303-592, 303-777, 303-860, 720-232, 720-330, 720-465, 720-707, 983-200 |
| El Paso County | El Paso County includes Colorado Springs, the U.S. Air Force Academy, and Fort Carson, blending military, tourism, tech, and healthcare industries. Most numbers use the 719 area code, and prefixes help distinguish Colorado Springs numbers from nearby rural towns. A Colorado Springs reverse phone lookup can quickly verify a missed call. Population: ~740,000 Major Cities: Colorado Springs, Fountain, Monument Area Codes: 719 Common Prefixes: 719-200, 719-219, 719-282, 719-390, 719-520, 719-574, 719-578, 719-634, 719-687 |
| Arapahoe County | Arapahoe County covers parts of Denver’s southeast metro, including Aurora, Centennial, and Littleton. Numbers are mostly in the 303 and 720 area codes, with 983 also appearing. This region is known for its suburban business parks, retail centers, and easy access to Denver. A Aurora CO phone number lookup or 720 reverse lookup can confirm caller details. Population: ~654,000 Major Cities: Aurora, Centennial, Littleton, Englewood, Greenwood Village Area Codes: 303, 720, 983 Common Prefixes: 303-409, 303-773, 303-794, 303-858, 720-229, 720-312, 720-432, 720-949, 983-215 |
| Jefferson County | Jefferson County stretches from Denver’s western suburbs to the Rocky Mountain foothills, combining urban communities and outdoor recreation hubs. Numbers are typically in the 303, 720, and 983 area codes. A Lakewood CO reverse lookup or Golden CO phone search helps confirm a caller’s location. Population: ~582,000 Major Cities: Lakewood, Arvada (part), Golden, Wheat Ridge, Edgewater Area Codes: 303, 720, 983 Common Prefixes: 303-202, 303-271, 303-384, 303-914, 720-222, 720-289, 720-497, 720-980, 983-230 |
| Adams County | Adams County includes major industrial zones, Denver International Airport, and suburbs like Commerce City and Brighton. The county’s phone numbers are mainly 303, 720, and 983, with some 970 in the northern areas. Prefixes identify whether a call is from the airport area, industrial parks, or residential neighborhoods. Population: ~527,000 Major Cities: Thornton, Commerce City, Brighton, Northglenn, Federal Heights Area Codes: 303, 720, 983, 970 Common Prefixes: 303-289, 303-288, 303-450, 303-920, 720-322, 720-374, 720-606, 720-773, 983-245 |
| Boulder County | Boulder County blends high-tech business, academia, and outdoor recreation, anchored by the city of Boulder and the University of Colorado. Most numbers are in the 303, 720, and 983 area codes. A Boulder reverse phone lookup quickly confirms if a call is from within the county. Population: ~330,000 Major Cities: Boulder, Longmont, Lafayette, Louisville, Erie (part) Area Codes: 303, 720, 983 Common Prefixes: 303-413, 303-442, 303-494, 303-786, 720-240, 720-310, 720-494, 720-600, 983-252 |
| Larimer County | Larimer County includes Fort Collins, Loveland, and Estes Park, known for its mix of higher education, breweries, and access to Rocky Mountain National Park. Numbers use the 970 area code almost exclusively. Population: ~374,000 Major Cities: Fort Collins, Loveland, Estes Park, Berthoud (part) Area Codes: 970 Common Prefixes: 970-217, 970-221, 970-226, 970-229, 970-310, 970-493, 970-498, 970-667, 970-669 |
| Douglas County | Douglas County is a fast-growing suburban region south of Denver, with communities like Castle Rock and Parker. Phone numbers are usually 303, 720, or 983. Population: ~375,000 Major Cities: Castle Rock, Parker, Lone Tree, Highlands Ranch Area Codes: 303, 720, 983 Common Prefixes: 303-660, 303-688, 303-805, 303-841, 720-200, 720-279, 720-294, 720-851, 983-260 |
| Weld County | Weld County covers a vast agricultural area, anchored by the city of Greeley. Numbers are mostly in the 970 area code, with some overlap in 303/720 in southern portions. Population: ~350,000 Major Cities: Greeley, Evans, Windsor, Firestone, Frederick Area Codes: 970, 303, 720 Common Prefixes: 970-302, 970-336, 970-347, 970-352, 970-356, 303-833, 303-485, 720-652 |
| Pueblo County | Pueblo County is known for its steel production, agriculture, and historic riverwalk. Phone numbers are primarily in the 719 area code. Population: ~169,000 Major Cities: Pueblo, Pueblo West Area Codes: 719 Common Prefixes: 719-214, 719-240, 719-251, 719-543, 719-544, 719-553, 719-562, 719-583 |
| Mesa County | Mesa County includes Grand Junction, the largest city on Colorado’s Western Slope, and is a hub for healthcare, energy, and tourism. Numbers use the 970 area code. Population: ~160,000 Major Cities: Grand Junction, Fruita, Palisade Area Codes: 970 Common Prefixes: 970-201, 970-241, 970-242, 970-243, 970-254, 970-255, 970-434, 970-464 |
| Broomfield County | Broomfield County is a smaller but fast-growing county that overlaps Denver’s metro area, blending tech business parks with residential neighborhoods. Numbers are mainly 303, 720, and 983. Population: ~77,000 Major Cities: Broomfield Area Codes: 303, 720, 983 Common Prefixes: 303-438, 303-469, 303-466, 720-887, 720-890, 720-887, 983-275 |
Colorado Reverse Phone Lookup – Identify 303, 719, 720, 970 & 983 Numbers
Trying to figure out who’s behind that Colorado phone call or text? Our Colorado reverse phone lookup tool makes it simple to identify unknown callers and trace phone numbers by Colorado area code. Just type the number into the search bar to instantly reveal details for any number from:
- 303 area code – covering Denver, Boulder, and surrounding suburbs.
- 719 area code – serving Colorado Springs, Pueblo, and southern Colorado.
- 720 area code – overlapping 303 for the Denver metro area, Aurora, and nearby cities.
- 970 area code – covering Fort Collins, Grand Junction, Greeley, and northern/western Colorado.
- 983 area code – newly introduced overlay for the 303/720 region.
With one quick search, you’ll uncover the caller’s name, city, phone carrier, Colorado prefix number, and matching Colorado phone directory records in seconds. Whether you’re running a Denver phone number lookup, Colorado Springs reverse phone search, Fort Collins phone number lookup, or checking any other Colorado area code, you can confirm the caller’s identity before answering, calling back, or blocking the number.
🔍 How to Trace the Owner of a Colorado Phone Number for Free: Step-by-Step Guide
Got an unfamiliar Colorado phone number calling or texting you? Whether it’s a free 303 reverse lookup for a Denver landline, a free 719 phone number search for a Colorado Springs caller, or a free 970 area code check from Fort Collins, understanding how Colorado phone numbers are structured can give you valuable clues before you even run a full search.
By breaking down the area code, prefix number (central office code), and subscriber number, you can often narrow a call’s origin to a specific city — and sometimes even the neighborhood. This free Colorado phone lookup guide will show you how to read a phone number using the North American Numbering Plan (NANP) and combine it with a free Colorado reverse phone lookup tool for the most accurate results.
🌎 Country Code
All U.S. phone numbers, including those from Colorado, begin with the country code +1 when dialed from abroad. This instantly confirms the call is U.S.-based, helping you filter out international spam for free before wasting time on it.
Example: +1-303-XXX-XXXX. The +1 shows it’s a U.S. number. In this case, the 303 area code covers Denver, Boulder, and surrounding areas, making a free Denver phone number lookup the logical next step.
📍 Area Code (NPA – Numbering Plan Area)
The first three digits after the country code are the area code, which identifies the general region of the call. Colorado has six primary area codes:
- 303 Area Code – Denver, Boulder, Aurora.
- 719 Area Code – Colorado Springs, Pueblo, Cañon City.
- 720 Area Code – Overlay for Denver metro & Front Range.
- 970 Area Code – Fort Collins, Grand Junction, Greeley.
- 983 Area Code – Overlay for Northern & Western Colorado regions.
Example: 719-555-XXXX. The 719 area code points to Colorado Springs and surrounding southern Colorado communities, making a free Colorado Springs phone lookup the best move to confirm the caller’s identity.
🔢 Prefix Number (NXX – Central Office Code)
The next three digits after the area code are the prefix number, which is assigned to a specific city, neighborhood, or phone carrier within that area code. When paired with the area code, this can help you pinpoint the number’s likely origin for free before running a full search.
Example: 970-241-XXXX. Prefix 241 is associated with Grand Junction, so using a free Grand Junction reverse phone search could confirm who’s calling.
Pro tip: Suspect a spoofed call? Compare the prefix against legitimate Colorado exchanges using a free Colorado phone prefix directory to see if it matches the claimed location.
🔐 Subscriber Number
The last four digits of a phone number are called the subscriber number. These digits identify the specific phone line assigned to a person or business.
On their own, subscriber numbers don’t reveal a location — but when combined with the area code and prefix number, they make up a complete phone number that can be searched to return exact results.
Example: 303-555-7890.
- 303 – Area Code (Denver region)
- 555 – Prefix Number (specific to part of Denver)
- 7890 – Subscriber Number (unique to this line)
Together, this full number can be entered into a free Colorado reverse phone lookup to find the caller’s name, carrier, and public records.
Why This Matters for Free Colorado Reverse Phone Lookup
Breaking down a Colorado number before running a search helps you:
- Quickly identify whether a call is coming from Denver, Colorado Springs, Fort Collins, Boulder, or another Colorado city.
- Spot suspicious or spoofed numbers before answering.
- Confirm for free if a number is truly local or from out of state.
- Decide whether to answer, block, or investigate further without wasting time or money
🚀 Take the Next Step — Search Any Colorado Number for Free
Enter the number into our free Colorado reverse phone lookup search bar to instantly see the caller’s name, location, carrier, and public records. Whether it’s a free 303 reverse lookup for Denver, a free 719 phone number search for Colorado Springs, or a free 970 reverse lookup for Fort Collins, our database covers every Colorado area code and prefix so you can know exactly who’s calling before you pick up.
📱 Real Example: How to Trace a Colorado Phone Number for Free
If you’ve ever asked yourself “Who just called me from this Colorado number?”, you can often find out for free before paying for a detailed report. This simple step-by-step process works whether you’re doing a free 720 reverse lookup for Aurora, a free 719 phone number search for Colorado Springs, or a free 970 lookup for Grand Junction and the Western Slope.
Example number: 📞 720-328-9476
Step 1: Check the Country Code
When dialing internationally, a +1 before the number means it’s from the United States — including Colorado. This quick check lets you filter out foreign spam calls before you dig deeper.
📍 +1 = United StatesStep 2: Identify the Area Code (720)
The first three digits are the area code. Here, 720 is used across the Denver metro and Front Range communities like Aurora, Centennial, Westminster, and Lakewood.
📍 Area Code 720 = Denver Metro / Front RangeRunning a free 720 reverse phone lookup will usually show you the general city or county tied to the number.
Step 3: Look at the Prefix (328)
The prefix — the next three digits — is also called the central office code. In this case, 328 is often linked to numbers from Aurora and parts of eastern Denver County.
📍 Prefix 328 = Aurora / East DenverThe area code + prefix combination is one of the fastest ways to narrow a call’s origin from a whole metro area down to a specific part of town.
Step 4: Understand the Subscriber Number (9476)
The last four digits, called the subscriber number, identify the exact phone line — like a house number on a street:
- On its own, it won’t tell you the location.
- When paired with the area code and prefix, it can be searched in a free Colorado reverse phone directory to uncover details like the caller’s name, exact city, and phone carrier.
Full breakdown so far:
📍 720 (Denver Metro) + 328 (Aurora / East Denver prefix) + 9476 (individual line)Step 5 – Confirm with Multiple Sources
To make sure you’ve got the right information:
- Search "720-328 Colorado prefix location" in a reliable phone database.
- Check our Colorado phone directory for possible matches.
- Use a free Colorado reverse phone lookup to pull name, location, and any public records linked to the number.
Final Result for This Example
Breaking it down:
📍 720-328-9476 is most likely a personal or business line registered in Aurora, Colorado.You now know:
- It’s a Colorado number.
- It’s from the Aurora / East Denver area.
- It’s not from Colorado Springs, Fort Collins, or Western Slope cities like Durango or Grand Junction.
Search Any Colorado Phone Number for Free
Type the number into our Colorado reverse phone lookup tool to instantly see the caller’s name, city, carrier, and public records. Whether you’re doing a 720 reverse lookup for Aurora, a 303 search for Denver, or a 970 lookup for Fort Collins, our database covers all Colorado area codes and counties.
📣 What Colorado Residents Are Saying About COPhoneLookup
Colorado Reverse Phone Lookup: Frequently Asked Questions
1. What is a Colorado reverse phone lookup?
A Colorado reverse phone lookup lets you search any phone number to uncover details about the caller—such as their name, location, phone carrier, and more. It’s the fastest way to identify unfamiliar callers, verify who’s behind a number, or flag potential spam calls from Colorado area codes like 303, 719, 720, 970, or 983.
2. How do I run a reverse phone lookup for a Colorado number?
Type the full 10-digit Colorado phone number into our search bar. Our database scans multiple public and proprietary sources to find details like the owner’s name, address, and carrier. Whether you need a 303 reverse lookup for Denver, a 719 phone number search for Colorado Springs, or a 970 reverse lookup for Fort Collins, our tool makes it simple.
3. Is it legal to use reverse phone lookup services in Colorado?
Yes. Reverse phone lookups are legal in Colorado and rely on publicly available records. You must use the information responsibly and avoid violating privacy or harassment laws.
4. What are the main area codes in Colorado?
Colorado has five primary area codes:
- 303 – Denver, Boulder, Aurora
- 719 – Colorado Springs, Pueblo, Cañon City
- 720 – Overlay serving Denver metro and surrounding areas
- 970 – Fort Collins, Grand Junction, Greeley, mountain and western regions
- 983 – Overlay serving parts of northern and western Colorado
5. Can I look up both landline and cell phone numbers in Colorado?
Yes. Our Colorado reverse phone lookup can search both mobile and landline numbers. Some mobile records may have limited details due to carrier privacy restrictions.
6. What type of information can I get from a Colorado reverse phone lookup?
Depending on availability, you might see:
- Caller’s full name
- Past and current addresses
- Phone carrier and line type
- Linked relatives or associates
- Public records or connected social media profiles
7. How reliable is the data from Colorado reverse phone lookup services?
Accuracy depends on how recently the database was updated. We refresh our Colorado records frequently to ensure you get the most precise results. For important searches, cross-check with other reputable sources.
8. Are there free options for reverse phone lookup in Colorado?
Yes—some free Colorado reverse phone lookup tools display basic info like city and carrier. More detailed reports, such as background checks or property records, usually require a paid search.
9. Why does Colorado have multiple area codes in the same region?
Population growth and increased demand for phone numbers led to overlapping area codes. For example, Denver uses 303 and 720, while Fort Collins uses 970 and sometimes 983.
10. How can I spot spam or scam calls from Colorado numbers?
Our system flags numbers with known spam or scam activity. You can also check the FCC and FTC complaint databases for Colorado phone numbers linked to fraudulent calls.
11. Can you tell if a Colorado number is a VoIP line?
Yes. Many VoIP numbers are used by telemarketers or scammers, and our tool can often detect them.
12. What does the prefix in a Colorado phone number mean?
The prefix—the three digits after the area code—narrows the location to a smaller area or exchange. Example:
- 303-555 = Central Denver
- 719-547 = Pueblo West
- 970-241 = Grand Junction
13. How can I block unwanted calls from Colorado numbers?
Use your phone’s built-in blocking features, register with the National Do Not Call Registry, or activate your carrier’s spam-blocking tools.
14. Are certain Colorado area codes more likely to get spam calls?
Yes—high population areas like 303 (Denver) and 720 (Denver metro) tend to get more spam calls due to the volume of active numbers.
15. Can I confirm if a number belongs to a Colorado business?
Yes. Our reverse phone lookup can reveal the business name, location, and sometimes the industry.
16. How often is your Colorado reverse phone lookup data updated?
Our Colorado records are refreshed regularly—some updated daily—to provide the most accurate search results.
17. Can reverse phone lookup find someone’s address in Colorado?
Yes, if the address is part of public records. Always follow legal and privacy guidelines when using this information.
18. Do reverse phone lookups work for unlisted Colorado numbers?
Results may be limited, but in many cases we can still provide partial information such as the city or carrier.
19. How do I report a suspicious Colorado number?
File a report with the FTC or FCC, and flag the number in our system so other Colorado residents are alerted.
20. Is there a mobile-friendly way to do Colorado reverse phone lookups?
Yes—our site works seamlessly on any mobile device, so you can run a search from anywhere.
21. Can I use reverse phone lookup to reconnect with someone in Colorado?
If their number is still active, you may be able to find updated contact info and reconnect.
22. Can I find out the time zone for a Colorado phone number?
Yes. Most Colorado phone numbers operate on Mountain Standard Time (MST) in the winter and Mountain Daylight Time (MDT) during daylight saving time. Colorado observes daylight saving across the state, so numbers from area codes like 303, 719, 720, 970, and 983 all follow the same time zone shifts. Knowing this can help you identify the best time to call someone back or determine if a late-night call might be spam.
23. Can I look up toll-free numbers linked to Colorado businesses?
Absolutely. Many Colorado-based companies use toll-free numbers (starting with 800, 888, 877, 866, or 855) for customer service, sales, and reservations. Our Colorado reverse phone lookup can identify the company name, location of its headquarters, and even its industry—helpful for confirming whether a toll-free call is from a legitimate Denver business or a scammer posing as one.
24. How can I tell if a Colorado phone number is spoofed?
Scammers often disguise calls with local Colorado area codes like 303 (Denver), 719 (Colorado Springs), 970 (Fort Collins), or 720 (Denver metro overlay) to appear trustworthy. This tactic, called neighbor spoofing, tricks people into answering. Running a Colorado reverse phone lookup before picking up can help confirm if the number truly belongs to a local resident, business, or agency—or if it’s been flagged as fraudulent.
25. How do I run a 303 Reverse Lookup for a Denver number?
Simply enter the full 10-digit number starting with 303 into our search tool. Our system instantly checks databases for details like the caller’s name, address, carrier, and whether the number is tied to a business in Denver, Lakewood, Boulder, or other nearby cities.
26. Can I use a 303 Phone Number Lookup to find a local business in Denver?
Yes. If you receive a 303 call you think is from a business, our tool can reveal its name, street address, business type, and sometimes linked websites or social media profiles. This is handy for confirming restaurant reservations, retail callbacks, or contractor follow-ups in the Denver metro area.
27. What’s the best way to check if a call from a 719 number is spam?
For numbers in Colorado Springs, Pueblo, or Canon City, a 719 Reverse Lookup can pull up spam reports, user comments, and complaint records from other Colorado residents. If the number has been flagged multiple times, it’s likely a robocall or telemarketer.
28. How do I run a 970 Reverse Lookup for calls from Northern Colorado?
A 970 Reverse Lookup covers Fort Collins, Loveland, Greeley, Grand Junction, and many mountain towns. Just enter the full number to see the caller’s name, possible location, and whether it’s a residential or business line.
29. Can I use a 720 Phone Number Lookup to check cell numbers in Denver or Aurora?
Yes. Whether it’s a mobile phone or landline, our 720 lookup can return details like the carrier, owner’s name, and city. This works for numbers from Denver, Aurora, Thornton, Westminster, and surrounding suburbs.
30. What’s the difference between a Colorado Springs Phone Number Lookup and a 719 Reverse Lookup?
A Colorado Springs Phone Number Lookup focuses on calls from Colorado Springs specifically, while a 719 Reverse Lookup covers all numbers in the southern Colorado region, including Pueblo, Alamosa, and rural counties.
31. Can I check if a 983 number is a VoIP line?
Yes. Our 983 Reverse Lookup can identify if a number is a landline, mobile, or VoIP (Voice over Internet Protocol) service. VoIP lines are often used by call centers and scammers, so spotting them can help you decide whether to answer.
32. How do I identify robocalls from Fort Collins or Boulder numbers?
Robocalls in the 303, 720, or 970 area codes may claim to be from local businesses or agencies. A quick lookup will reveal if the number is genuine or flagged for spam. You can also check for matching business listings in Larimer or Boulder County.
33. Can I use a Western Slope Phone Number Lookup to confirm a business call?
Yes. For calls from Grand Junction, Durango, or Steamboat Springs (mostly in the 970 area code), a reverse lookup can verify whether the number belongs to a legitimate local company or a scam operation.
34. What are some common prefixes for Denver phone numbers?
Denver numbers in the 303 area code often begin with prefixes like 303-321, 303-333, 303-455, and 303-733. Recognizing these can help narrow your search to specific neighborhoods or exchanges.
35. How do I reconnect with old contacts using a Colorado Springs 719 Reverse Lookup?
If you have an old 719 number, a reverse lookup can help find updated addresses, new numbers, or even email information for former friends, coworkers, or classmates.
36. Can I find out which carrier owns a Fort Collins 970 number?
Yes. Our lookup tool shows carrier details for 970 numbers, letting you see if it’s Verizon, AT&T, T-Mobile, Comcast, or another provider—information useful for spotting potential VoIP calls.
37. How do I block unwanted calls from 720 numbers?
First, confirm the caller’s identity with a 720 lookup. Then use your phone’s block feature or your carrier’s spam-blocking service. You can also report the number to the FTC’s Do Not Call registry complaint form.
38. Can a Boulder Phone Number Lookup show past addresses?
Sometimes, yes. If the number has been linked to multiple addresses in public records, our results may list both current and former residences or business locations.
39. Are all 983 numbers based in Colorado?
Yes. The 983 area code is an overlay for 303 and 720, meaning it can be assigned anywhere in the Denver metro and surrounding areas. A lookup can pinpoint the specific city.
40. Why does my Denver Phone Number Lookup show multiple addresses?
If a number’s owner has moved or uses it for both personal and business purposes, you may see several addresses tied to the same number. This can help trace the number’s history.
Additional Resources for Understanding Colorado’s Area Codes and Phone Numbers
- Colorado.gov – The official Colorado state government site, providing public records access, state agency contacts, and resources for verifying phone numbers, caller identities, and business listings.
- North American Numbering Plan Administration (NANPA) – Detailed information on Colorado’s area codes (303, 719, 720, 970, and 983), overlays, and prefix assignments, with historical numbering updates.
- Federal Communications Commission (FCC) – Federal guidelines on phone number regulations, robocall prevention strategies, and consumer protection resources for Colorado residents.
- National Institute of Standards and Technology (NIST) – Telecommunications standards and technical guidelines that impact number assignments and accuracy nationwide.
- U.S. Census Bureau – Colorado Population & Geographic Data – Demographic and geographic insights explaining how Colorado’s population growth and distribution shape area code allocations and phone usage.