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

From Cleveland, Ohio: Take I-71 South to S.R. 30S.R. 30 to I-75 South. I-75 South to S.R. 33 (Exit 110) West. West on S.R. 33 to St. Marys (33 becomes 29 at St. Marys). Stay on four-lane road to S.R. 364. Exit on 364 and follow signs. From Columbus, Ohio: West on S.R. 33 to St. Marys (33 becomes 29 at St. Marys). Stay on four-lane road to S.R. 364. Go South to 703 then East on 730/364 to park entrance. From Cincinnati, Ohio: I-75 North to Exit 110 (S.R. 33) West. S.R. 33 West to St. Marys (33 becomes 29 at St. Marys). Exit at 364, then South (turn left) to 703 East (turn left) on 703/364 to park entrance. From Toledo, Ohio: South on I-75 to Exit 110 (S.R. 33) West. West on S.R. 33 to St. Marys (33 becomes 29 at St. Marys). Exit at 364, then South (turn left) to 703 East (turn left) on 703/364 to park entrance. From Celina, Ohio: Take S.R. 703 East toward St. Marys Park Entrance will be on right (seven miles). Park entrance is located off S.R. 703, approximately two miles West of St. Marys.