Osceola is the county seat of Mississippi County, and is also the seat of one of two judicial districts. Blytheville was named a secondary judicial district in 1901. Anchoring the town square is the 1912 neoclassical Mississippi County Courthouse, with a copper-roofed dome. The courthouse is bordered by the Hale Avenue Historic District and other structures on the National Historic Register of Historic Places. The Mississippi County Historical Center is located in a 1904 building that once housed a dry goods store.