Grand Lake St. Marys State Park
RV Guide


If the road ever takes your RV to Ohio, make sure that you at least pass by the Grand Lake St. Marys State Park, one of the hidden gems of the state with the best sunsets and the most fascinating sunrises you will ever see here. The park is located on the wonderful 13,500-acre Grand Lake in the counties of Mercer and Auglaize. Grand Lake is an inland lake and absolutely huge, but quite shallow at the same time, only going up to seven feet in depth. However, it is gorgeous, which makes a visit to the St. Marys State Park a must for all nature lovers and campers of all ages. The park itself spans across 591 acres west of the town of St. Marys and southeast of Celina. RV campers can learn about the history of the area, have fun on the lake, even do some fishing if they feel like it, but most of all, they will be able to enjoy the gorgeous surroundings and just relax, far away from the noise and the fast city life.

RV Rentals in Grand Lake St. Marys State Park



Since the park is looped around Grand Lake, there are many roads you can take to get here. The park itself is located in western Ohio, which means that if you are coming from the east, the closest town is St. Marys. The road to the park is quite narrow and its condition is not the best, however, you should not have too much trouble driving there. You will go through some populated areas, which means that asking for precise directions will be easy, but also means that you need to pay extra attention to the road to avoid accidents. The terrain is quite flat so it won’t be difficult to drive on. If you are coming from Lima, you will need to cover about 23 miles or 37 kilometers driving southwest.

When it comes to parking, in the campsites the park has a limitation of two vehicles per site. However, daily visitors can park on the visitor parking lot, located near the bike rental station, close to the park entrance. A smaller parking lot is located by the Convention & Visitors Bureau and the park’s main office, from where you can walk to the fishing pier.


Public Transportation

Campgrounds and parking in Grand Lake St. Marys State Park

Campsites in Grand Lake St. Marys State Park

Reservations camping

Wapakoneta KOA

Roughly between Toledo and Cincinnati lies Wapakoneta, Ohio, the birthplace of Neil Armstrong. The city's location off I-75 means you can ease into Wapakoneta KOA from wherever you've been and recharge. Bring your rigs of up to 80 feet long and settle in at a deluxe patio site complete with full hookups, up to 50-amp service, patio furniture, propane grill and campfire experience. Water/electric gravel pads are also available. Camper's can purchase propane and firewood at the convenient campground store. There’s a Kamping Kitchen and snack bar to keep you well fed, and a heated pool and mini golf course to keep you active. Stay updated with Wi-Fi and cable TV. Pets are welcome.

Grand Lake St. Marys State Park Campground

The campground is pretty huge and is located right by the Grand Lake, allowing campers to enjoy the proximity of the water. A total of 217 campsites are available to visitors, 148 of which are electric, 33 with full hookups, 10 are standard, and seven of them are actually cabins you can rent. The campground is flat and surrounded by trees that provide a nice shade. All the roads are paved. Hot showers, flush toilets, and the dump station are close by, and many of the sites have a great view of the lake. Each of the sites has a fire ring, grill, and a table for those alfresco dinners. A maximum of two pets per site are allowed, and they must be on a leash.

Seasonal activities in Grand Lake St. Marys State Park


Learning about History

When you set up your camper or trailer here, you can learn a lot about the history of the area and the entire Grand Lake St. Marys State Park. If you go to the visitors center, you can learn that the Grand Lake was actually constructed in the 19th century to be used as a reservoir for the canals that connected the Lake Erie and the Ohio River. When it was built, it was the largest man-made lake in the world! It was considered to be one of the top destinations for oil drilling since oil was discovered here in the late 1800s. Before that, the area was inhabited by Native Americans, who were driven out by the army of General Anthony Wayne who was sent here by President George Washington to resolve the Northwest Indian War. Bring your kids along and allow them to learn about the rich history of the area and their country – they will surely find this knowledge useful when they go back to school!

Observing Nature

RV campers who wish to unwind, enjoy the silence, and forget about the world can spend their day simply observing the wonders of nature that surround them. Green Lake used to be a swampy prairie that was flooded when the lake was created. Now, the area is filled with wetlands, prairie ecosystems, and woodlands that provide shade. Bird watchers can photograph geese, ducks, swans, loons, and grebes, but also see birds such as herons and egrets. Cormorants and ospreys often reside here, as well as bald eagles which have returned here to nest in the Wildlife Refuge. Some of the mammals you can see are beavers, raccoons, fox squirrels, mink, and white-tailed deer – but do not come close to them. Let them be and just observe how they act in the wild.


If you are an avid cyclist, or if you just want to have a relaxing bike ride through the park, you’d be happy to hear that this is one of the most beautiful areas you can cycle through and build your leg muscles. Campers can rent bicycles in the camp store or simply bring their own, which will surely give them more freedom. Once you get on the bike, you can take one of the roads around the campground, cycle to the camp lagoon where the boating ramps are, check out the cedar cabins, nature centers, and simply enjoy the cool breeze coming from the water. Take a Red Wing Black Bird Trail and enjoy the surroundings, soak up the enchanting scents of mother nature, and just enjoy your time off and connect with your roots.



The big beautiful lake is home to many fish species, so it is no wonder why fishing is one of the most popular activities in the Grand Lake St. Marys State Park. Anglers can wake up at the crack of dawn and test their skills casting their baits for game fish such as crappie, bluegill, yellow perch, and bass. There is also a hatchery nearby which raises channel catfish, bass, walleye, and saugeye, which are all meant for stocking in the public waters of the state. If you are not the one to carry fishing equipment in your rig, you can rent everything in the camp store and just return it once you’re done.

Boating and Water Sports

One more thing to do on the lake is boating! Pack your gear, leave your camper in the campgrounds, and head out into the open water for a day of adventuring. Unlimited horsepower boats are allowed on the lake, however, the key is to be respectful to others who also want to enjoy the lake and not have your boat too close to the shore to allow the swimmer to have fun. Nine launch ramps are available for visitors but bear in mind that a 300-foot no-wake zone was established 52 miles of shore. Boats cannot enter the wildlife refuge, on the southeast part of the lake. Apart from boating, canoeing, kayaking, and water skiing are allowed as well, so everyone can find their own adrenaline fix.


Even though the Grand Lake is quite shallow, it can still provide plenty of summertime fun opportunities such as swimming! One of the best ways to unwind and cool off in the hot summer’s day is to dip your toes into the water and just relax, an exercise in the water, and have a little swim to get your cardio up. Four public swimming beaches are available to the visitors who want to spend a nice day outside. Luckily, the lake is quite close to the campground as well, so you can leave your RV and head straight to the beach and make a day out of it! When it comes to lifeguards, they are there on the weekends and holidays, so be careful when you go into the water, especially if you are taking children with you. Of course, be careful not to leave any garbage behind to preserve the surroundings and make a positive impact on our planet.