Henry County is a county located in the U.S. state of Virginia. As of the 2020 census, the population was 50,948. The county seat is usually identified as Martinsville; however, the administration building, county courthouse, and Henry County Sheriff's Office are located on Kings Mountain Road in Collinsville. The Henry County Adult Detention Center is located on DuPont Road in Henry County, just south of Martinsville. Henry County is part of the Martinsville Micropolitan Statistical Area.