Lake Arthur, the central feature of the park, spans 3,225 acres with 42 miles of shoreline, attracting over one million visitors every year. The lake is a warm-water fishery, home to fish species like northern pike, largemouth bass, channel catfish, black crappie, and bluegill. Visitors can swim at two beaches: Lakeview Beach on the North Shore, a 656-foot sand beach, and Pleasant Valley Beach on the South Shore, a 400-foot turf and sand beach with amenities like sand volleyball, playgrounds, showers, changing facilities, and snack bars. The beaches are open daily from Memorial Day Weekend to Labor Day, 8:00 a.m. to sunset, with swimming at your own risk as there is no lifeguard.