406 acres. Deciduous woodlands; coniferous plantations; aspen parkland; oak savannah; prairie; wet meadows; river and lakes.
The park features hiking/ski trails and a steam powered flour mill, as well as a campground and swimming beach. Old Mill State Park is operated by the Minnesota DNR.
Sharp-tailed Grouse, Snowy, (winter only) Long-eared, Short-eared and Northern Saw-whet Owls, Pileated Woodpecker, vireos, wrens, warblers and finches. Rarities seen here include Clark’s Nutcracker and Mountain Bluebird.
Vehicle permits are required. Area map and bird checklist are available. Picnic area and camping available. Birding can be excellent with over one hundred species commonly found in the park.