The National Lakeshore owns the water from the ordinary high water mark to 300 feet offshore. The 1,530 acres Dunes Nature Preserve makes up the bulk of the eastern part of the park, and includes most of the park's hiking trails and dune landscape. The beaches were formed by winds coming off of Lake Michigan, which drop sand when the wind hits plants, dunes and hills.
The Tremonts, Mt.Tom, 192 feet above lake level; Mt. Holden, 184 ft. above lake level, and Mt. Jackson 176 feet above lake level.