Morgan County is a county in the north central part of the U.S. state of Alabama. As of the 2010 census the population was 119,490. The county seat is Decatur. The county was created by the Alabama Territorial legislature on February 6, 1818 from land acquired from the Cherokee Indians in the Treaty of Turkeytown, and was originally called Cotaco County. On June 14, 1821 it was renamed in honor of American Revolutionary War General Daniel Morgan of Virginia.