Elk Rock State Park is a state park in Marion County, Iowa, United States, situated on both upstream banks of Red Rock Reservoir. Knoxville at the southwest and Pella to the northeast are the nearest cities. On north are Otley and Monroe; at the west is Pleasantville. Elk Rock has two areas: the main area and the "Mile Long Bridge" area. The bridge area is much smaller than the main area but has a couple of shelters and a restroom facility.