Notice: A new automated gate will be installed at Rosaryville State Park the week of November 15th 2021, and will be in use shortly after. Entry fees will not change.
Prince George's County
Rosaryville State Park
7805 West Marlton Avenue
Upper Marlboro, MD 20772
Hours: Park is Open 8 a.m. to sunset. All vehicles must exit the park before the gate closes at sunset. If locked in, call Park Watch at 1- 800 825 7275.
Rosaryville is a 982 acre day-use park with miles of trails for hiking, biking and equestrians. To gain access to Rosaryville State Park, make a right turn into the entrance just south of Osborne Road while traveling south on U.S. 301. The park is also the location of the historic Mount Airy Mansion. Parties, great and small, weddings, births and visits from seven presidents have left their mark, lending a wonderful feeling of expectancy to this lovely old home.