Area Code 303
303 area code is being used for dialing/telecommunication purposes in Colorado, covering 26 major cities and 8 counties, according to (NANP) North American Numbering Plan for 3-digit Numbering Plan Area (NPA) code. All the areas using NPA code 303 is part of MST (Mountain Standard Time) timezone.
303 Area Code Covers 26 Cities
Check this below table to know 26 major cities (having more than 20,000 population) in Colorado using numbering plan area code 303 for dialing/telecommunication purposes.
| City | ZIP Codes | Population |
|---|---|---|
| Arvada, CO | 7 | 123,066 |
| Aurora, CO | 17 | 387,349 |
| Boulder, CO | 11 | 106,598 |
| Brighton, CO | 3 | 40,569 |
| Broomfield, CO | 1 | 73,946 |
| Castle Rock, CO | 3 | 74,065 |
| Centennial, CO | 3 | 107,702 |
| Commerce City, CO | 3 | 63,050 |
| Denver, CO | 54 | 710,800 |
| Englewood, CO | 4 | 33,634 |
| Highlands Ranch, CO | 5 | 101,514 |
| Lafayette, CO | 1 | 30,295 |
| Lakewood, CO | 4 | 156,149 |
| Littleton, CO | 9 | 45,531 |
| Longmont, CO | 4 | 98,282 |
| Loveland, CO | 3 | 76,500 |
| Northglenn, CO | 3 | 37,948 |
| Parker, CO | 2 | 58,733 |
| Thornton, CO | 1 | 141,799 |
| Westminster, CO | 4 | 115,502 |
| Wheat Ridge, CO | 2 | 32,263 |
8 Counties Using 303 as Area Code
303 area code is being used in 8 counties of Colorado for dialing/telecommunication purposes.
- Adams County, CO
- Arapahoe County, CO
- Boulder County, CO
- Broomfield County, CO
- Denver County, CO
- Douglas County, CO
- Jefferson County, CO
- Larimer County, CO
25 More NPA Codes Related to Area Code 303
1 or more of these 25 NPA codes are being used in the same or adjacent states of Colorado in the United States.
- 307 Area Code
- 308 Area Code
- 316 Area Code
- 385 Area Code
- 402 Area Code
- 405 Area Code
- 435 Area Code
- 480 Area Code
- 505 Area Code
- 520 Area Code
- 531 Area Code
- 539 Area Code
- 575 Area Code
- 580 Area Code
- 602 Area Code
- 620 Area Code
- 623 Area Code
- 719 Area Code
- 720 Area Code
- 785 Area Code
- 801 Area Code
- 913 Area Code
- 918 Area Code
- 928 Area Code
- 970 Area Code