Operated by Guest Services, Inc. Open 6 days a week, trail rides available 5 days a week. Tues. - Fri. 12 pm - 6 pm, Sat. & Sun. 9 am - 5 pm. Closed Mon., Thanksgiving Day, Christmas Day and New YearÃ¢â‚¬â„¢s Day. Rock Creek Park Horse Center is duty authorized concession of Rock Creek Park.