Hartselle is the second largest city in Morgan County, Alabama, United States, 13 miles south of Decatur. It is part of the Decatur Metropolitan Area and the Huntsville-Decatur Combined Statistical Area. As of the 2020 census, the population of the city was 15,455. Hartselle was founded in 1869 with the arrival of the South and North Alabama Railroad. It takes its name from George Hartsell, one of the railroad's owners. The post office opened in 1873.