County Route 504, abbreviated CR 504, is a county highway in the U.S. state of New Jersey. The highway extends 15.94 miles (25.65 kilometers) from Main Road (Alt County Route 655) in Montville (across the Montclair-Boonton Line tracks from U.S. Route 202) to McLean Boulevard (Route 20) in Paterson, where the road continues as Route 20.