Three Sisters Group Site is a newly constructed accessible site located across the road from the Rock Creek Horse Camp. The site is equipped with a 20' x 30' pavillion, 8 picnic tables, group size BBQ grill, group size fire ring with handcrafted wooden benches around it, 2 vault toilets, parking for 25 vehicles, and a capacity to hold 75 people. There is no water or electricity. Reservations can be made by contacting the Darby Ranger Station at (406) 821-3913. Office hours are Monday - Friday; 8:00 a.m. to 4:30 p.m.