A 303 reads Denver tenure
303 has the original 1947 prestige — distinct from the 720 overlay assigned to newer Denver-metro lines since 1998.
Get a 303 Denver, 720 metro overlay, 970 northern/western Colorado mountains, 719 Colorado Springs/southern CO or any of Colorado's 5 area codes on the phone you already own. The Centennial State's full prefix map — pick the code your customers will recognise.
Colorado has 5 active area codes — 303, 720, 970 and 2 more. You can get a virtual Colorado phone number from any of these area codes through CallMama without a US address or SIM card.
Colorado was assigned a single area code in 1947: 303, covering the entire state. For four decades the single code carried Denver, the Front Range and the mountain resorts as one geographic region.
The splits came as Colorado's population accelerated. 719 split from 303 in 1988 for the southern half (Colorado Springs, Pueblo, the San Luis Valley). 970 split from 303 in 1995 for northern and western Colorado (Fort Collins, Boulder/wait — Boulder stayed with 303 — Greeley, Aspen, Vail, Grand Junction).
Denver metro's growth then forced overlays: 720 was added over 303 in 1998 — one of the earliest US overlay codes — and 983 was added in 2023 over 719 to serve continued Colorado Springs growth. Today Denver and Front Range cellular numbers may be assigned either 303 or 720 at random.
Colorado's 303 was one of the first US area codes to receive an "all-services overlay" when 720 was added in 1998. Before this, the FCC required dialed numbers to include 1+ for overlay calls; Colorado was at the forefront of mandatory 10-digit dialing within the same metro area.
Every Colorado area code plotted at its primary city. Click any marker for that code's details. Overlays share geography with their parent code — they're shown offset on the map for visibility.
Every Colorado metro covered by a different prefix. Open any card to view its full detail page.
Find your city, find its area code, then activate a number with that prefix.
A local Colorado prefix outperforms an out-of-state cell at every customer touchpoint.
303 has the original 1947 prestige — distinct from the 720 overlay assigned to newer Denver-metro lines since 1998.
Aspen, Vail, Steamboat Springs, Fort Collins, Boulder-adjacent communities all use 970. A 970 prefix reads as Western Slope or Northern Front Range — distinct from Denver itself.
US Air Force Academy, NORAD, Peterson SFB, Space Force HQ all sit in 719 territory. A 719 prefix reads as native to Colorado Springs and the Pikes Peak region.
Selling across Colorado? Add 303 Denver, 970 mountains and 719 Springs lines on one account — full state coverage on one device.
Colorado sits in Mountain Time aligned with Salt Lake, Phoenix, Albuquerque. A CO prefix tells Mountain West and SW clients you're on their schedule.
Cancel service and your Colorado number is reserved free for 12 months — keep your 303 or 970 across seasonal moves between Denver and the mountains.
Each Colorado area code covers a distinct region. Here's how the population breaks down.
Source: US Census Bureau / ACS estimates.
Pick the digits, install the app, take the first call. That's the whole sequence.
CallMama generates 10–20 available numbers in any Colorado area code. Vanity patterns supported.
Install CallMama on the device you already use. Sign in once — your Colorado number is linked.
Inbound and outbound on the same device. Local Colorado caller ID on every outgoing call.
Search by state, city, or number — then click any code to open its detail page. Colorado is in here too.
| State | Area Codes | Time Zone | Count |
|---|---|---|---|
| Alabama | 205251256334659938 | CT | 6 |
| Alaska | 907 | AKT | 1 |
| Arizona | 480520602623928 | MST | 5 |
| Arkansas | 479501870 | CT | 3 |
| California | 213310408415510619650714818916 | PT | 10 |
| Colorado | 303719720970 | MT | 4 |
| Connecticut | 203475860959 | ET | 4 |
| Delaware | 302 | ET | 1 |
| District of Columbia | 202 | ET | 1 |
| Florida | 239305321407561727786813850904954 | ET* | 11 |
| Georgia | 229404470478678706762770912 | ET | 9 |
| Hawaii | 808 | HST | 1 |
| Idaho | 208986 | MT* | 2 |
| Illinois | 217224309312331618630708773779815847872 | CT | 13 |
| Indiana | 219260317463574765812930 | ET* | 8 |
| Iowa | 319515563641712 | CT | 5 |
| Kansas | 316620785913 | CT* | 4 |
| Kentucky | 270364502606859 | ET* | 5 |
| Louisiana | 225318337504985 | CT | 5 |
| Maine | 207 | ET | 1 |
| Maryland | 240301410443667 | ET | 5 |
| Massachusetts | 339351413508617774781857978 | ET | 9 |
| Michigan | 231248269313517586616734810906947989 | ET* | 12 |
| Minnesota | 218320507612651763952 | CT | 7 |
| Mississippi | 228601662769 | CT | 4 |
| Missouri | 314417573636660816 | CT | 6 |
| Montana | 406 | MT | 1 |
| Nebraska | 308402531 | CT* | 3 |
| Nevada | 702725775 | PT | 3 |
| New Hampshire | 603 | ET | 1 |
| New Jersey | 201551609732848856862908973 | ET | 9 |
| New Mexico | 505575 | MT | 2 |
| New York | 212315332347516518585607631646680716718838845914917929934 | ET | 19 |
| North Carolina | 252336704743828910919980984 | ET | 9 |
| North Dakota | 701 | CT* | 1 |
| Ohio | 216234330380419440513567614740937 | ET | 11 |
| Oklahoma | 405539580918 | CT | 4 |
| Oregon | 458503541971 | PT* | 4 |
| Pennsylvania | 215267272412445484570610717724814878 | ET | 12 |
| Rhode Island | 401 | ET | 1 |
| South Carolina | 803843854864 | ET | 4 |
| South Dakota | 605 | CT* | 1 |
| Tennessee | 423615629731865901931 | CT* | 7 |
| Texas | 210214254281325346361409430432469512682713737806817830832903 | CT* | 20 |
| Utah | 385435801 | MT | 3 |
| Vermont | 802 | ET | 1 |
| Virginia | 276434540571703757804 | ET | 7 |
| Washington | 206253360425509564 | PT | 6 |
| West Virginia | 304681 | ET | 2 |
| Wisconsin | 262414534608715920 | CT | 6 |
| Wyoming | 307 | MT | 1 |
| Puerto Rico | 787939 | AST | 2 |
One tap to install. One more to call. It really is that simple.