Free. Guided tour $6; $4 (ages 6-16). Children 4 and under are not permitted due to safety regulations. Reservations are required for guided tour.
Visitor center open daily 8-4:30, June-Sept.; Mon.-Fri. 8-4:30, rest of year. Ranger-guided tours lasting approximately 30 minutes are given daily 8:30-11 and 1-3:30, June-Sept.; Mon.-Fri. at 10 and 2, rest of year. Closed Jan. 1, Thanksgiving and Christmas. Phone ahead to confirm schedule. Allow 2 hours minimum.