Colorado Area Codes
Directory of all 6 telephone area codes assigned to Colorado.
Colorado phone numbers are served by 6 area codes operating in the Mountain timezone.Because an overlay is active, 10-digit dialing is mandatory across much of the state. No area codes in Colorado are currently flagged as high-risk scams.
Most populated prefix: area code 303 (Colorado)
All Area Codes in Colorado
Area Code 303
Denver, Aurora, Lakewood, Thornton, Arvada, Westminster, Centennial, Boulder, Longmont, Castle Rock
Area Code 719
Colorado Springs, Pueblo, Cañon City, Monument, Alamosa, Trinidad, Woodland Park, Lamar, La Junta, Salida
Area Code 720
Denver, Aurora, Lakewood, Thornton, Arvada, Westminster, Centennial, Boulder, Longmont, Castle Rock
Area Code 748
Fort Collins, Greeley, Loveland, Grand Junction, Windsor, Fountain, Evans, Johnstown, Montrose, Firestone
Area Code 970
Fort Collins, Greeley, Loveland, Grand Junction, Windsor, Fountain, Evans, Johnstown, Montrose, Firestone
Area Code 983
Denver, Aurora, Lakewood, Thornton, Arvada, Westminster, Centennial, Boulder, Longmont, Castle Rock
Major Cities Served by Colorado Area Codes
The most populous urban centers and census places covered by Colorado's area codes, ranked by population.
Colorado Area Code FAQs
Quick answers to common questions about Colorado telephone area codes.
How many area codes does Colorado have?
Colorado has 6 area codes: 303, 719, 720, 748, 970, 983.
What timezone do Colorado area codes use?
Colorado area codes operate in the Mountain timezone.
What is the most populated area code in Colorado?
Area code 303 is the most populous prefix in Colorado based on covered city population.
Which Colorado area codes share an overlay?
303 and 720, 303 and 983, 720 and 983, 748 and 970. Overlay codes serve the same area, which is why 10-digit dialing is required.
Are there scam area codes in Colorado?
Colorado has no area codes currently flagged as high-risk scams.
About Colorado Area Codes & Phone Dialing Rules
When placing calls within Colorado, ten-digit dialing (area code + 7-digit telephone number) is required in overlay regions where multiple area codes serve the same geographic boundaries.