The US 79 south / KY 3240 east  Clarksville intersects the Russellville Bypass, a beltway around Russellville in Logan County in south central Kentucky, at mile 0.0 and the KY 178 intersection is at mile 1.564.
U.S. Route 79 (US 79) enters Kentucky from Tennessee in Todd County west of Guthrie and runs northeast into Logan County, terminating at a junction with US 68, US 68 Business, and Kentucky Route 80 (KY 80) in Russellville. The route continues northeast through rural areas of Logan County until it comes to an intersection with US 431, the Russellville Bypass, on the south side of Russellville 10.713 miles (17.241 km) from the Todd County line. 10.606 miles (17.069 km) from the Kentucky-Tennessee border, US 79 crosses into Logan County where it becomes known as Clarksville Road. 
