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. Its seasonal campsite for visitors 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.