McLain is a town in Greene County, Mississippi, United States. The population was 441 at the 2010 census, down from 603 at the 2000 census.

Greene County is a county located on the southeast border of the U.S. state of Mississippi. As of the 2020 census, the population was 13,530. Its county seat is Leakesville. Established in 1811, the county was named for General Nathanael Greene of the American Revolutionary War.