The Old Alexander House is a historic house on the campus of Southern Arkansas University in Magnolia, Arkansas. Originally built in rural Columbia County in 1855 by Samuel Alexander, this single-story dogtrot house is one of the oldest buildings in the county, and one of its few surviving antebellum structures. The house was listed on the National Register of Historic Places in 1979. In 2017 it was moved from its rural location to the university campus, where it is slated to be used as part of its rural studies program.