State Route 99 is a long east–west highway in Middle Tennessee. The route travels through large sections of rural areas and for most of the length is a secondary highway. The route begins near Waynesboro and ends in Bradyville after logging 128.4 mi (206.6 km) and passing through six counties.The highway begins at an intersection with U.S. Route 64 as a secondary route that was the former route of US 64 in Wayne County. From there it travels through Lewis County where it meets U.S. Route 412.