Admission to Grand Lake St. Marys State Park is free.
- Open daily dawn to dusk
- Location: (Map It) On State Route 703 just west of St. Marys, Ohio
- Phone: 419-394-3611
- Web: Click here
Grand Lake St. Marys State Park: Originally constructed as a feeder reservoir for the Miami-Erie Canal, Grand Lake St. Marys was for many years recognized as the largest man-made reservoir in the world. This large lake is the gateway to swimming, boating, camping and fishing in one of Ohio’s oldest state parks. The campground contains 210 sites of which 142 are equipped with electricity. Facilities include flush toilets, laundry, showers and a dump station. The campground also offers a “camper’s only” swimming beach, boat launch and boat docks/tie-ups. Two air-conditioned Camper Cabins and two Rent-A-Tepees with camping gear may be rented from May-October. Two spacious Cedar Cabins with all the amenities of a fully-equipped RV are also available for daily or weekly rental. A seasonal naturalist holds scheduled programs Thursday through Saturday night. Boats with no limits on horsepower are permitted on the lake. Five state operated launch ramps provide access to the lake. Several private launch ramps also exist along the shallow shoreline. Fuel, boat rentals and seasonal dock rentals are available.