After this intersection, the route becomes unnamed as it passes commercial areas before passing farms and making a turn to the north, becoming county maintained again. The road passes through a mix of homes and businesses parks before heading near more farmland, running a short distance to the west of Norfolk Southern's Lehigh Line. After intersecting CR 612, CR 523 turns east onto Flemington-Whitehouse Road and passes over the Lehigh Line, at which point it runs between the South Branch Raritan River to the north and an industrial facility to the south. The road crosses the South Branch Raritan River into Readington Township, where it turns northeast and then north into a mix of woods, farms, and residential neighborhoods. The route curves to the north-northeast as it crosses CR 629 and continues to the CR 620 intersection near more residential areas. CR 523 comes to the community of Whitehouse Station, where the route becomes Main Street as it passes homes, crossing NJ Transit's Raritan Valley Line near White House station. A short distance later, CR 523 intersects US 22 and turns northwest to form a brief concurrency with that route on a four-lane divided highway. After the US 22 overlap, CR 523 continues north on two-lane undivided Oldwick Road, entering wooded areas with some homes. The road is briefly a four-lane divided highway as it comes to an interchange providing access to the UNICOM Science and Technology Park. The road becomes two lanes and undivided again as it crosses into Tewksbury Township and reaches an interchange with I-78, with a park and ride lot located at the southwest corner. Past this interchange, the route passes a mix of fields and woods with a few residences before coming to the southern terminus of CR 517. At this point, CR 517 heads north and CR 523 makes a right turn to head east on Lamington Road into more rural areas.