Just went for the day, but plan on going back as soon as possible for a few nights. The lake is cool and quiet, tucked away in the center of Custer park. Several trails and tons of fishing spots. There are vaulted toilets and a shower house. Camp sites are next to the lake and spaced well apart. One of my favorite spot s in the Black Hills, saw a buffalo on the drive there too.
This is a delayed review. Went there last August with some friends. They stayed in a tent, I slept in my hammock. Campground is tucked in the woods but in walking distance of the beautiful Deerfield Lake. Camp sites are well maintained, large, and separated enough to not bother your neighbors.