Allegheny Islands State Park is a 50-acre park reachable only by boat, made up of two alluvial islands and seven shoals in the Allegheny River in Allegheny County. The islands are heavily vegetated and undeveloped, among the few left in a natural state, and are home to many animals and plants. They flood frequently. The upper island covers about 14 acres, opposite the mouth of Black Run near the lock and dam. Organized group camping is the only overnight use; contact the park office before visiting.