CR 518 begins at an intersection with Route 29/Route 165 in Lambertville, Hunterdon County, heading east on two-lane undivided Brunswick Avenue. The road climbs in elevation heading east through wooded residential areas before turning southeast and crossing into West Amwell Township and becoming Brunswick Pike. The route winds east through forested areas with some homes before entering a mix of farmland, woods, and residences. CR 518 turns northeast and enters Hopewell Township in Mercer County and immediately intersects CR 601 before coming to the CR 579 junction. At this intersection, the road becomes Lambertville-Hopewell Road and continues east, intersecting CR 612 in Woodsville and Route 31.