State Route 187 (SR 187, OH 187) is a 8.23-mile (13.24 km) north–south state highway in the central portion of the U.S. state of Ohio. The southern terminus of SR 187 is at a T-intersection with SR 56 approximately 4.25 miles (6.84 km) northwest of London. Its northern terminus is at a T-intersection with SR 29 about 1 mile (1.6 km) to the southeast of Mechanicsburg.