Hours: Grounds open daily 7 a.m.-dusk, May-Oct.; daily 9 a.m.-dusk, Mar.-Apr. and Nov.-Dec.; Fri.-Sun. 9 a.m.-dusk, in Feb. Visitor center daily 9-6, May-Oct.; daily 9-5, Mar.-Apr. and Nov.-Dec.; Fri.-Sun. 9-5, in Feb. Closed Thanksgiving, day after Thanksgiving, Christmas Eve, Christmas and Dec. 31. Holiday hours vary; phone ahead. Last admission 1 hour before closing. Allow 2 hours minimum.