It travels south-to-north through portions of Cocke, Greene and Hamblen counties.

SR 340 begins in the mountains of Cocke County at an intersection with US 25/US 70/SR 9 just west of Del Rio along the banks of the French Broad River.

It winds its way northward through the mountains before entering farmland and passing through Parrottsville, where it has an intersection with US 321/SR 35.

It then passes through some ridges and rolling countryside before crossing into Greene County.

The highway continues northeast through farmland before coming to an end at an intersection with SR 113.