US 17 heads north out of Warrenton as James Madison Highway. The highway follows Cedar Run through a gap between Waters Mountain and Pignut Mountain. In Old Tavern, US 17 meets the southern end of SR 245 (Old Tavern Road). The U.S. Highway continues northwest from Old Tavern as Winchester Road to the southern edge of Marshall, where the highway meets I-66 at a diamond interchange. US 17 joins I-66 heading west while US 17 Business continues into the center of Marshall. West of Marshall, I-66 and US 17 have an interchange with the other end of US 17 Business and SR 55. The three highways head northwest along the freeway to Delaplane, where I-66 and the two other highways split. Just north of the partial interchange, SR 55 (John Marshall Highway) diverges from US 17 to parallel I-66 toward Front Royal. US 17 follows Winchester Road, a two-lane highway, through the center of Delaplane, where the U.S. Highway crosses Goose Creek and intersects Norfolk Southern's B-Line at grade. The U.S. Highway continues north past the entrance to Sky Meadows State Park to its junction with US 50 (John Mosby Highway) in Paris. US 17 runs concurrently with US 50 for the remainder of its course.