Creelsboro Natural Bridge, also called Rock House or the Rockhouse, is a natural arch near Creelsboro in southwestern Russell County, Kentucky, beside the Cumberland River. Unlike the more common sandstone arches, it is a meander natural bridge formed when river erosion cut through a cliff at a sharp bend, creating an opening in Upper Ordovician silty dolomite of the Cumberland Formation. Jim Creek flows through it before reaching the river. With a span of 104 feet, it ranks among the nation’s largest natural bridges, including the largest in the eastern United States. First recorded in 1770, it later became a popular camping place and was designated a National Natural Landmark in 1987.