Grand Lake St. Marys State Park is an American state park, west of St. Marys, and south-east of Celina, 23mi south-west of Lima in the north-western part of Ohio.Grand Lake covers in Mercer and Auglaize counties. Grand Lake is the largest inland lake in Ohio in terms of area, but is very shallow, with an average depth of only 5to. The park is open for year-round recreation, including boating, fishing, swimming and hunting. The park consists of the lake and park facilities scattered all around the shore intermingled with private property and a facility operated by Wright State University.HistoryPresident George Washington dispatched General Anthony Wayne and his army to the Northwest Territory to put down the Northwest Indian War. After the Native Americans were driven out and west, the land was opened to settlement by Anglo-Americans. Homesteaders, including soldiers from Wayne's army arrived soon after.Grand Lake St. Marys was constructed in the early 19th century as a reservoir for the Miami and Erie Canal, which connected the Ohio River with Lake Erie. At one time the lake was the world's largest man-made lake. The canal system thrived for about thirty years in the mid-to-late 19th century before it was replaced by the railroads. In the 1890s oil was discovered in the area, and oil derricks were set up in the lake sometime around 1891. This made Grand Lake the location for the first off shore oil drilling to take place. The lake became one of Ohio's first state parks in 1949 with recreational facilities built in the following years.
