CR 523 begins at an intersection with Route 29 (Main Street) in Stockton, Hunterdon County, heading northeast on Stockton-Flemington Road through wooded residential areas.

CR 523 intersects Route 12 at Dvoor's Circle and crosses into Flemington a short distance later, becoming municipally-maintained Mine Street, which is lined with homes.

At this point, CR 523 resumes county maintenance and becomes a divided highway as it passes residential subdivisions, narrowing back into an undivided road as it turns east and intersects Route 31.

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.

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 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.