The Bergen County Line is a former branch line of the Erie Railroad that diverges off the Eire Main Line between Glen Rock and Secaucus Junction. The line is 1 mile shorter than the Main Line and travel times on local trains are 3 minutes faster because there is one fewer stop on the Bergen County Line between Ridgewood and Secaucus Junction. The branch line has two-tracks for its entire length, with the Pascack Valley line sharing the first three miles and same two tracks between Laurel Interlocking just beyond Secaucus Junction (the line has 4 tracks through Secaucus and into the Bergen Tunnel into Hoboken) and Pascack Junction one mile south of the first stop of Rutherford.

Service on the line is every 2 hours or better. During daytime hours on weekdays hourly or better, during weekdays when hourly service is provided most trains run to and from Suffern. On weekends and evenings most trains terminate at Waldwick, with connecting Main Line service pn most trips north to Suffern. The reason for the change in service patterns is that Bergen County Line local trains are 3 minutes faster than Main Line local trains, on weekdays when the Bergen County Line runs hourly, it can provide hourly service at the shared stops between Waldwick and Suffern. On evenings and weekends, the Main Line still runs hourly, with the Bergen County Line less consistent so Main Line trains provide the bulk of the nearly hourly service between Waldwick and Suffern.

Some Bergen County Line trains (3 daily Port Jervis-bound; 4 Weekday, 1 weekends Hoboken-bound) continue north to and from Port Jervis (running under contract with Metro-North), some of these trains stop at just Rutherford and Radburn, some add stops at Plauderville and Broadway (skipping Garfiend and Westmont) while others make all stops.

The line is not-electrified and all trains use push-pull Comet Coaches, or MultiLevels (MultiLevels are never on trains to and from Port Jervis) with a diesel locomotive on the end of the train facing away from Hoboken Terminal.