Kinderkamack comes from the language of the Lenape Native Americans, meaning "place of ceremonial dance and worship." During the American Revolutionary War, General Lafayette's division camped in what is now Oradell at Kinderkamack and Soldier Hill Roads.
While signage directing traffic to County Route 503 exists on westbound NJ 3, CR 503 officially begins at NJ 120. Traffic following NJ 120 around the Meadowlands Sports Complex exits (or enters) in East Rutherford, while CR 503 traffic continues straight ahead into Carlstadt. Through the industrial area of the borough of Carlstadt, the four-lane highway, divided in some sections, is called Washington Avenue.
At Moonachie Avenue, CR 503 crosses into Moonachie and becomes known as Moonachie Road. The highway continues as a two-lane road through Little Ferry, there called Liberty Street, where it intersects US 46. Entering South Hackensack, the road again becomes Moonachie Road and continues into Hackensack. At the end of Moonachie Road, CR 503 then turns left onto the four-lane River Road, which passes under Interstate 80 and the Susquehanna tracks. Near the Fairleigh Dickinson University campus, River Road becomes Hackensack Avenue, which shortly crosses NJ 4 and then the Coles Brook into River Edge.
Near the Steuben House in River Edge, CR 503 turns left onto Main Street and crosses the Pascack Valley Line at grade before turning northward onto Kinderkamack Road. CR 503 then continues north through Oradell, Emerson, Westwood, Hillsdale, Woodcliff Lake, Park Ridge, and Montvale. Most of this ten-mile stretch is two-lane road, but the northbound and southbound alignments split briefly in Montvale, where the highway again crosses the Pascack Valley Line at Grand Avenue.