State Route 705 (SR 705) is a state highway in western Ohio, a U.S. state. The highway's western terminus is in rural northwestern Darke County at SR 49 approximately 5.25 miles (8.45 km) southeast of Fort Recovery, and just a mile south of the Darke-Mercer County Line. Its eastern terminus is at SR 29 nearly 2.75 miles (4.43 km) northwest of Sidney.Established in the late 1930s, SR 705 connects the northern half of Darke County to the city of Sidney.