Somerville is a town in Morgan County, Alabama, United States. It is included in the Decatur Metropolitan Area, as well as the Huntsville-Decatur Combined Statistical Area. As of the 2010 census, the population of the town was 724, up from 347.Somerville was the county seat of Morgan County from 1818 to 1891, when the seat was moved to Decatur. The town was named for Robert M. Summerville, an officer killed in 1814 during the Creek Indian War. Initially incorporated on December 3, 1819, it is a few days older than the state. After its loss of the county seat in the 1890s, its incorporation lapsed. It was reorganized on December 1, 1955.