West Branch State Park in northeastern Ohio occupies more than 5,000 acres of land and 2,650 acres of water around the Michael J. Kirwan Reservoir on the west branch of the Mahoning River. Its modern landscape took shape in the mid-1960s, when the U.S. Army Corps of Engineers built the reservoir for recreation, water supply, flood control, and fish and wildlife management, and the state opened the park in 1966. Today it is defined by boating, fishing, swimming, camping, and extensive trails, while also preserving links to an older landscape where Native Americans and early settlers drew salt from the Mahoning River.