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.

Camping 

• 166 electric sites
• 38 non-electric sites
• Facilities include flush toilets, laundry, showers and a dump station.
• Pets are permitted except for the area in and around the Getaway Rentals
• Free WiFi for registered campers 
• “Camper’s only” swimming beach, boat launch and boat docks/tie-ups are available
• Seasonal naturalist programs are offered on weekends Memorial Day through Labor Day
• Full-service camp store loans games, fishing and sporting equipment to registered campers
• Bike rentals and miniature golf course

Getaway Rentals  

• 5 air-conditioned Camper Cabins may be rented April through October
• 2 spacious Cedar Cabins with all the amenities of a fully-equipped RV are also available for daily or weekly rental
• Pets are not permitted in the Getaway Rental units or area

Boating 

• Boats of unlimited horsepower are permitted on the lake
• 8 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
• A 300 foot no-wake zone has been established and is enforced around the lake's 52 miles of shoreline
• The state wildlife refuge, located on the southwest corner, is off limits to boats at all times

Fishing

• Year-round fishing offers crappie, bass, bluegill, walleye and yellow perch
• Valid Ohio fishing license is required

Swimming

• 4 public swimming beaches as well as other swimming areas provided for boaters
• Check for water quality advisories

Picnicking  

• 9 Picnic areas with tables and grills are located in scenic areas around the lake
• 4 picnic shelters are reservable online or by calling (866)-644-6727

Hunting

• Limited hunting is permitted in designated areas, hunting maps are available in the park office
• 70 seasonal duck blinds are available by a lottery administered by ODNR Division of Wildlife
• Valid Ohio hunting license is required

More To Do

• Basketball and volleyball courts
• Horseshoe pits
• Playground equipment
• Fur-Ever Friends Dog Park , thanks to the efforts of the volunteers of the Fur-Ever Friends Dog Park and the Celina Rotary Dog Park of the West Bank, is open and offers a place for your pets to frolick without a leash

Area Attractions

• Lake Loramie State Park, southeast of Grand Lake St. Marys, offers fishing, boating, swimming and camping.
• The Miami-Erie Trail, a 47-mile portion of the statewide Buckeye Trail, begins at Lake Loramie and passes within a mile and a half of Grand Lake St. Marys State Park • The Miami-Erie Trail terminates at Delphos, approximately 22 miles north of St. Marys
• St. Marys Fish Hatchery, located on the lake's eastern shore is operated by the ODNR Division of Wildlife • The hatchery raises saugeye, walleye, channel catfish and bass for distribution in the public fishing waters of the state
• The Neil Armstrong Air and Space Museum is located in Wapakoneta, Armstrong's boyhood home
• The Auglaize-Mercer County Convention/Visitors Bureau is located next to the park office. For more information on area attractions, stop by or call 800-860-4726

Nature of the Area

Although hard to imagine, at one time the Grand Lake St. Marys region was part of a vast forest wilderness that stretched from the Allegheny Mountains of Pennsylvania to the prairies of Illinois • Today, in place of this forest are fields of corn, soybeans and wheat

In addition to forests, pre-settlement Ohio contained large prairies and wetlands • The land which now lies beneath St. Marys reservoir was once a vast wet prairie • Today, the park contains varying habitats including woodlands, wetlands, and prairies in addition to the surrounding croplands

Grand Lake St. Marys lies along one of the country's major migration routes • Water birds using the lake as a resting stop include Canada geese, ducks, grebes, swans, egrets, loons, herons, cormorants and ospreys • Many ducks, geese and heron also nest here • Bald eagles, magnificent birds long absent from the area, have again nested on the southwest corner of the lake at the wildlife refuge • Other animals of the park include fox squirrel, mink, raccoon, beaver, coyote, white-tailed deer and many others

History of the Area

The area in and around Grand lake St. Marys State Park played an important part in the development of the Northwest territory • The St. Marys River served as a vital link between the Great Lakes and the Ohio River • Because of this heavy water traffic, the renegades Simon and James Girty established a trading post, which eventually evolved into the town of St. Marys • General “Mad” Anthony Wayne passed through the area in 1794 during this march to drive out the Shawnee, which culminated in the Battle of Fallen Timbers • Some of Wayne's men returned here to make their homes

In 1837, work commenced on a reservoir for the Miami-Erie canal to maintain the canal’s five-foot water depth • Workers using hand tools were paid 35 cents a day and a jigger of whiskey to keep malaria away • At its completion in 1845, 13,500-acre Grand Lake was the largest man-made lake in the world • The lake was connected to the canal by a three-mile feeder

The canal prospered until the coming of the railroads in the 1870s • The area experienced another boom in the late 1890s when oil was discovered • For a time the lake was dotted with oil derricks • Today a pile of rocks near the center of the lake marks the spot of the last producing well

Grand Lake St. Marys and other canal feeder lakes in the state were the first areas to be dedicated as Ohio state parks in 1949