Area code 303 serves the Denver metropolitan area in Colorado, including cities like Boulder, Lakewood, and Aurora. Established in 1947, it originally covered the entire state before being reduced due to splits and overlays. Today, it shares the region with overlays 720 and 983, requiring ten-digit dialing. Denver is a booming hub for tech, aerospace, outdoor recreation, and progressive culture. Area code 303 retains a legacy appeal, often used in marketing, branding, and community pride to evoke authenticity and original ties to Colorado’s Front Range. It remains one of the most recognizable area codes in the Mountain West.
Locations for Area Code - 303
Browse all cities and areas that belong to this area code.
Arvada
- State: CO
- Population: 115,368
- Latitude: 39.80276, Longitude: -105.08748
- Elevation: 1629 m
Aurora
- State: CO
- Population: 359,407
- Latitude: 39.72943, Longitude: -104.83192
- Elevation: 1648 m
Boulder
- State: CO
- Population: 106,803
- Latitude: 40.01499, Longitude: -105.27055
- Elevation: 1624 m
Brighton
- State: CO
- Population: 37,585
- Latitude: 39.98526, Longitude: -104.82053
- Elevation: 1519 m
Broomfield
- State: CO
- Population: 65,065
- Latitude: 39.92054, Longitude: -105.08665
- Elevation: 1644 m
Castle Rock
- State: CO
- Population: 55,591
- Latitude: 39.37221, Longitude: -104.85609
- Elevation: 1897 m
Castlewood
- State: CO
- Population: 25,271
- Latitude: 39.58471, Longitude: -104.90109
- Elevation: 1746 m
Columbine
- State: CO
- Population: 24,280
- Latitude: 39.58777, Longitude: -105.06943
- Elevation: 1688 m
Commerce City
- State: CO
- Population: 53,696
- Latitude: 39.80832, Longitude: -104.93387
- Elevation: 1572 m
Denver
- State: CO
- Population: 729,019
- Latitude: 39.73915, Longitude: -104.9847
- Elevation: 1609 m
Englewood
- State: CO
- Population: 33,082
- Latitude: 39.64777, Longitude: -104.98776
- Elevation: 1637 m
Highlands Ranch
- State: CO
- Population: 96,713
- Latitude: 39.55388, Longitude: -104.96943
- Elevation: 1732 m
Ken Caryl
- State: CO
- Population: 32,438
- Latitude: 39.57582, Longitude: -105.11221
- Elevation: 1756 m
Lafayette
- State: CO
- Population: 27,729
- Latitude: 39.9936, Longitude: -105.08971
- Elevation: 1588 m
Lakewood
- State: CO
- Population: 729,019
- Latitude: 39.73915, Longitude: -104.9847
- Elevation: 1609 m
Littleton
- State: CO
- Population: 46,368
- Latitude: 39.61332, Longitude: -105.01665
- Elevation: 1631 m
Longmont
- State: CO
- Population: 92,088
- Latitude: 40.16721, Longitude: -105.10193
- Elevation: 1519 m
Loveland
- State: CO
- Population: 75,182
- Latitude: 40.39776, Longitude: -105.07498
- Elevation: 1519 m
Northglenn
- State: CO
- Population: 39,197
- Latitude: 39.88554, Longitude: -104.9872
- Elevation: 1639 m
Parker
- State: CO
- Population: 49,550
- Latitude: 39.5186, Longitude: -104.76136
- Elevation: 1789 m
Southglenn
- State: CO
- Population: 42,268
- Latitude: 39.58721, Longitude: -104.95276
- Elevation: 1705 m
Thornton
- State: CO
- Population: 133,451
- Latitude: 39.86804, Longitude: -104.97192
- Elevation: 1631 m
Westminster
- State: CO
- Population: 116,317
- Latitude: 39.83665, Longitude: -105.0372
- Elevation: 1641 m
Wheat Ridge
- State: CO
- Population: 31,192
- Latitude: 39.7661, Longitude: -105.07721
- Elevation: 1664 m
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