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.

The highway goes through rural areas in Darke County, passing through the villages of New Weston and Osgood heading east.

There are no stretches of this state route that are inclusive within the National Highway System.