Open
Open year-round. Reservations available up to six months in advance through ReserveOhio.
About
Grand Lake St. Marys State Park Campground is located on the shores of Grand Lake St. Marys, Ohio's largest inland lake at 13,500 acres, straddling Mercer and Auglaize counties in western Ohio. The campground offers a diverse mix of around 200 campsites: 148 electric sites, 33 full hookup sites with water and sewer, and 10 standard non-electric sites, plus seven rustic rental cabins with lake views. All roads and site pads are paved, with both pull-through and back-in options available.
Facilities are extensive for a state park campground. Modern restrooms feature flush toilets and hot showers. A full-service camp store offers supplies and bike rentals, and loans fishing gear and games to registered campers. Recreation options include a swimming pool with splash pad, playground, horseshoe pits, and mini golf. Boat docks provide direct lake access for fishing and boating, though swimming in the lake itself is prohibited due to water quality concerns. Each campsite includes a fire ring, grill, and picnic table.
Reservations can be made up to six months in advance through ReserveOhio or by calling (866) 644-6727. The campground operates year-round and welcomes RVs, though reviewers note that pull-through sites work best for units under 35 feet if towing a vehicle.
Directions
From I-75, take US-33 west toward St. Marys. The park entrance is located off State Route 703 on the east side of Grand Lake St. Marys, approximately 3 miles west of St. Marys.