State Route 578 (SR 578) was a short north–south state highway in northwestern Ohio, a U.S. state. SR 578 ranked among the shortest state routes in the state, coming in at a length of just 0.19 miles (0.31 km). Its southern terminus was at SR 65 in Grand Rapids, and its northern terminus was at what was then U.S. Route 24 (US 24), just across the Maumee River and the Wood-Lucas county line from Grand Rapids. After SR 295 was extended from its southern terminus along the Maumee River and the former route of US 24, it took over all of SR 578 in 2012 thereby deleting the SR 578 designation.