Colorado Area Codes
6 active area codes · Denver · Population around 5,988,502
Colorado has 6 active area codes, serving cities like Denver, Colorado Springs, and Aurora. Of those, 5 are overlays covering ground another code already covers, which is why local calls there use all ten digits. The newest, 748, has been in service since July 7, 2025. Each code below links to its cities, carriers, timezone, and coverage map.
Colorado Area Code Map
What area codes does Colorado have?
- 303OverlayDenverMountain Time (MT) · 137 cities · 3,380,487
- 719Colorado SpringsMountain Time (MT) · 147 cities · 1,140,066
- 720OverlayDenverMountain Time (MT) · 137 cities · 3,380,487
- 748OverlayFort CollinsMountain Time (MT) · 176 cities · 1,253,161
- 970OverlayFort CollinsMountain Time (MT) · 176 cities · 1,253,161
- 983OverlayDenverMountain Time (MT) · 137 cities · 3,380,487
More than one of these codes covers 41 of the 64 counties in Colorado, and one county is covered by 5 of them. Each card counts the people inside that code's own boundary at the 2020 census. Adding all 6 gives 13,787,849, against the 5,773,714 the same census counts in those counties, because 8,014,135 residents fall inside more than one code.
Which cities are the largest in Colorado?
| # | City | Area Codes | Population |
|---|---|---|---|
| 1 | Denver | 303 / 720 / 983 | 729,019 |
| 2 | Colorado Springs | 719 | 493,554 |
| 3 | Aurora | 303 / 720 / 983 | 403,130 |
| 4 | Fort Collins | 970 / 748 | 170,924 |
| 5 | Lakewood | 303 / 720 / 983 | 156,868 |
| 6 | Thornton | 303 / 720 / 983 | 146,689 |
| 7 | Arvada | 303 / 720 / 983 | 121,873 |
| 8 | Westminster | 303 / 720 / 983 | 115,302 |
| 9 | Greeley | 970 / 748 | 114,363 |
| 10 | Pueblo | 719 | 111,166 |
How many phone prefixes does Colorado use?
The area codes in Colorado hold 2,922 assigned prefixes between them, listed under 107 distinct carrier names. A prefix is the three digits after the area code, and NANPA assigns each one to a single carrier. One of the 6 codes here — 748 — is newer than the NANPA extract behind these numbers, so its prefixes are not counted above.
Sources: City populations – U.S. Census Bureau PEP, Vintage 2024 (SUB-IP-EST2024-POP). State populations – the same program, Vintage 2025 (CO-EST2025-ALLDATA). Area-code footprint and county populations – 2020 Census Centers of Population, mapped against NANP area code boundaries. The share of each city inside a code is measured the same way, against Census place boundaries from the Census Bureau's TIGERweb service. Area code assignments – NANPA CO Code data. See our data methodology.
Frequently Asked Questions
How many area codes does Colorado have?
Colorado has 6 active area codes: 303, 719, 720, 748, 970, 983.
What is the main area code for Colorado?
Of the 6 area codes in Colorado, 303 is the oldest one still serving Denver, its largest city. 303 has been in service since 1947.
What are the largest cities in Colorado?
The largest cities in Colorado include Denver, Colorado Springs, Aurora, Fort Collins, Lakewood.
What is the total population of Colorado?
Colorado has an estimated total population of 5,988,502 based on US Census PEP 2024 data.
Do I have to dial ten digits in Colorado?
In the parts of Colorado covered by an overlay, yes. 5 of the 6 area codes here cover ground another code already covers, and where two codes share an area, local calls need the area code as well as the seven-digit number.
Why does Colorado have 6 area codes?
They arrived one at a time rather than all at once: 303 has been in service since 1947. 5 of the 6 are overlays, laid over a code that already covered the same ground instead of splitting its map in two. The most recent is 748, in service since July 7, 2025.
What is the newest area code in Colorado?
748, in service since July 7, 2025.
Is my county covered by more than one area code in Colorado?
It may be: more than one area code covers 41 of the 64 counties in Colorado, and one county there is covered by 5 of them. The table above shows which codes reach each of the largest cities.