State Route 146 is a relatively short north–south highway in Middle Tennessee. The road begins northwest of Centertown and ends in Smithville. The current length is 17.67 mi (28.4 km).

The highway begins at U.S. Highway 70S northwest of Centertown. It proceeds northward as Short Mountain Road. It turns east, then northeast as it moves around Short Mountain. After passing Short Mountain, SR-146 goes into DeKalb County as Short Mountain Highway where it continues northeast. Once in Smithville, SR-146 is called South Mountain St until its northern terminus at Highway 70.