Stone State Park is a state park in Iowa, United States, located in the bluffs and ravines adjacent to the Big Sioux River. The park is located on the northwestern edge of Sioux City and consists of 1,069 acres in Woodbury and Plymouth Counties, 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.