The Piney River is a 23.7-mile-long (38.1 km) tributary of the Duck River in Middle Tennessee in the United States. Via the Duck River, the Tennessee River, and the Ohio River, it is part of the Mississippi River watershed. The headwater tributaries of the Piney River rise in Dickson County, Tennessee, near the city of Dickson. Dickson is located on the "Tennessee Valley Divide", which corresponds for some distance with the downtown's Main Street.