Wyalusing State Park:

Wyalusing State Park established in 1917 rises 500 feet above the confluence of the Wisconsin and Mississippi rivers. One of Wisconsin’s oldest state parks, Wyalusing features family and group camps, hiking trails, a canoe trail, Native American burial mounds, bird watching, fishing, boating, bicycling, and picnicking near several scenic overlooks of the river valleys below. Wyalusing is one of the few state parks in the nation with an astronomical observatory offering free observations to the park visitors. 

Wyalusing State Park requires a fee to get in and enjoy the park. It is $7 per day or $25 for an annual pass for Wisconsin residents. Please visit here for the current fee schedule:http://dnr.wi.gov/topic/parks/admission.html