Highways head northwest through gaps in Big Ridge, Walker Mountain, then curve southwest through the Rich Valley. At the Washington–Scott county line, US 421 and US 58 veer northwest again and follow a curvaceous path through Shelly Ridge and Cove Ridge, after which the highways follow Cove Creek southwest through the valley of the North Fork Holston River until the highways turn northwest, cross the river, and pass through Hilton Gap in Pine Ridge.
The highways travel a route that includes gaps in Big Ridge, Walker Mountain, Rich Valley, Shelly Ridge, Cove Ridge, Cove Creek, and the North Fork Holston River. They then navigate through Hilton Gap in Pine Ridge.