Yellowstone Lake State Park is a state park of Wisconsin, United States, featuring a 455-acre reservoir on a tributary of the Pecatonica River. The state park is included in the 4,047-acre Yellowstone Lake State Wildlife Area. The park has 128 campsites and 5 group sites. There is a swimming area with sand beach, picnic areas, and playgrounds. Boat launch, boat rentals, fishing for bluegill, largemouth bass, walleye and channel catfish, with some northern pike and muskellunge.