Rosaryville is a 982 acre day-use park and the locationMount Airy Mansion located in Rosaryville of the historic Mount Airy Mansion. Miles of trails for hiking, biking and equestrians are available for day use. 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. Two pavilions, each accommodating 200 guests, are available for rent. A bathroom is a short distance from the pavilion area. A $150 security deposit is required for all pavilion rentals. For pavilion reservations at Rosaryville State Park please call 301-856-9656. The park offers deer bow hunting only. Be sure to consult your Maryland Guide to Hunting and Trapping for season dates and bag limits. Hunters may enter / remain on park property outside of the regular posted hours provided that they are engaged in legitimate, authorized hunting activity.