In the higher reaches of the mountains is pristine Crystal Lake. There's excellent hiking along interpretive and wildflower trails as well as camping, fossil hunting, and ice-cave exploration. The ice cave is a 6-mi hike from the 28-site campground; June is the best time to see the 30-foot ice pillars formed over the winter. There's a cabin 6 mi from the gate for snowmobilers, cross-country skiers, and snowshoers, but it's closed when the snow is too deep to navigate (which
is most of the winter). No motorized boats are allowed on the lake.