State Route 185 is an east to west secondary highway in Gibson County, Tennessee that is 7.67 miles (12.3 km) long. Its western terminus is in Dyer, Tennessee at the junction with U.S. Route 45W. Its eastern terminus is just outside of Bradford at TN 54. East of Dyer the highway is also called Poplar Grove Road.

The original western terminus was in Dyer at the intersection of Main Street (then US 45W) and Poplar Grove Road. In 2001, when US 45W was realigned to a newly constructed bypass route to the west of Dyer, SR 185 was extended through Dyer on Main Street and Yorkville Street (formerly SR 77) to the new US 45W. This change went unsigned until May 2008.