Littleton, CO utilizes an area code overlay in which area codes 303 and 720 serve the same geographic area. Area Code 303 was one of the original area codes established in 1947. At that time it covered the entire state of Colorado. The area code overlay was established in 1998. Ten digit dialing (area code + seven digit number) is necessary because two different homes in the same geographic area can have the same seven digit phone number but each would have a different area code.
In addition to Littleton, CO area codes 303 and 720 serve central Colorado including the larger cities and communities of Aurora, Boulder, Brighton, Broomfield, Castle Rock, Castlewood, Columbine, Commerce City, Denver, Englewood, Highlands Ranch, Ken Caryl, Lafayette, Lakewood, Littleton, Longmont, Loveland, Northglenn, Parker, Southglenn, Thornton, Westminster and Wheat Ridge in addition to many smaller communities.
Littleton, CO is located in Arapahoe County and observes the Mountain Time Zone. View our Times by Area Code tool.