Dewey's Pasture Complex Access provides boat ramp access to a 5,390-acre prairie pothole complex designated as a Registered Natural Landmark and Bird Conservation Area, featuring multiple parking areas and a 3+ mile mowed loop hiking trail through Lost Island Marsh and around Mud Lake.

The main parking lot is located off Highway B17 (300th Street) about 4 miles north of Highway 18 between Spencer and Ruthven, with additional facilities including restrooms at nearby Huston County Park and the Lost Island Nature Center.

The complex supports kayaking, canoeing, fishing, and hunting opportunities across its upland prairie, marsh, and oak forest habitats.