Stone State Park is a state park of Iowa, USA, located in the bluffs and ravines adjacent to the Big Sioux River. The park consists of 1,069 acres (433 ha) in Woodbury and Plymouth Counties near Sioux City, and overlooks the South Dakota-Iowa border. Stone Park is near the northernmost extent of the Loess Hills, and is at the transition from clay bluffs and prairie to sedimentary rock hills and bur oak forest along the Iowa side of the Big Sioux River.