Rocky Arbor State Park is a 244-acre Wisconsin state park in the Wisconsin Dells region, established in 1932 to protect a small but dramatic landscape of sandstone walls and ledges. The rock formed about 500 million years ago during the Late Cambrian, when shallow inland seas covered the area. Much later, the Wisconsin River cut channels through this tract before shifting about 1.5 miles east, leaving the exposed remains of its former gorge as a small creek began flowing the opposite way. Though modest in size, the park offers campgrounds, picnic areas, and trails that make these formations easily accessible in a major tourist region.