Ketchin Building, also known as the Fairfield County Historical Museum, is a historic building located at Winnsboro, Fairfield County, South Carolina. It was built about 1830, and is a three-story, five bay, Federal style brick building with a hipped roof. Originally built as a dwelling, it was sold in 1852 and was used as a school for girls until closed by the American Civil War. It was added to the National Register of Historic Places in 1971.