State Route 191 (abbreviated as SR 191) is a north–south state highway in northwestern Ohio, a U.S. state. SR 191's southern terminus is at U.S. Route 6 (US 6) approximately four miles (6.4 km) south of Stryker. Its northern terminus is at the concurrency of US 20A and US 127 in downtown West Unity. Between its southern terminus and Stryker, SR 191 runs parallel to, and to the east of, the Tiffin River.