I apologize for the error in my initial response. The boat ramp named Jefferson County is actually located in Illinois, not Wisconsin. It is located at the end of County Road 1900 E, off Route 14, in Jefferson County, Illinois.

Based on the latest information available, the Jefferson County boat ramp is a concrete boat ramp that is 16 feet wide. It services Rend Lake, which is a 19,000-acre reservoir located in southern Illinois. The lake is known for its excellent fishing opportunities, particularly for catfish, crappie, and bass.

A variety of watercraft are allowed on Rend Lake, including motorboats, sailboats, kayaks, canoes, and jet skis. However, all watercraft must comply with the Illinois Department of Natural Resources boating regulations, which include having the appropriate safety equipment on board and following speed limits and other rules of the waterway.

Overall, the Jefferson County boat ramp provides easy access to a beautiful and popular recreational area in southern Illinois.