The U.S. state of Colorado is served by five telephone area codes of the North American Numbering Plan (NANP).

• Area code 303 is the original area code assigned to the entire state when the first nationwide telephone numbering plan was created in 1947. Today it only serves the greater Denver Metropolitan Area.
• Area codes 720 and 983 are overlay codes for today's 303 numbering plan area (NPA).
• Area code 719 serves Colorado Springs and southeastern Colorado.
• Area code 970 serves northern and western Colorado.
• Area code 748 will be introduced to the northern and western areas of Colorado in 2026.

• Geography of Colorado
• List of North American Numbering Plan area codes

38°59′50″N 105°32′52″W / 38.9972°N 105.5478°W / 38.9972; -105.5478 (State of Colorado)