Chelsea is a city in Shelby County, Alabama, United States. It is part of the Birmingham metropolitan area. Chelsea was incorporated on March 1, 1996, with a population of 906. At the 2000 census the population was 2,949. According to the U.S. Census Bureau, the 2010 population for Chelsea was 10,183 and 14,126 in 2019. Its seasonal campsite and activities for visitors and others living in and around Chelsea is Hargis Retreat which began in 1984. Chelsea is widely considered the fastest growing city in Shelby County, which is the fastest growing county in the state of Alabama.
Chelsea is located near the central part of Shelby County at 33° 20' 24" N, -86° 37' 49" W (33.3401108 N, -86.6302625 W). The city is traversed by multiple county highways, as well as U.S. Route 280, which runs through the northern part of the city, leading northwest 19 mi (31 km) to downtown Birmingham, and east 12 mi (19 km) to Harpersville. Double Oak Mountain, a southern extension of the Appalachian Mountains, runs northwest of the city. Part of the city limits extend along US 280 on top of the ridge.