The Northern Branch Corridor Project is a proposed extension of the Hudson-Bergen Light Rail (HBLR) from its northern terminus into eastern Bergen County, New Jersey, initially proposed in 2001. If built, the new service would use the right-of-way of the Northern Branch on which the Erie Lackawanna Railroad ran passenger service until October 3, 1966, and is currently a lightly used, stub-ended freight rail line owned by CSX Transportation. The Northern Branch Corridor is at the foot of the west side of the Hudson Palisades in the Hackensack River valley, running for much of its length parallel to Overpeck Creek. After mixed reactions and extensive community input to a draft environmental impact statement (EIS), it was decided in 2013 to terminate the line at the Englewood Hospital and Medical Center. In March 2017 the Supplementary Draft Environmental Impact Statement was approved by the Federal Transit Administration allowing for a period of public reaction. A separately-conceived and funded bridge at 69th Street in North Bergen, necessary for operation of the system, has been completed. In 2017 NJ Transit estimated that the line would open in 2029.

The Northern Branch is a railroad line that runs from Jersey City to Northvale in northeastern New Jersey, and formerly extended further into New York State. The line was constructed in 1859 by the Northern Railroad of New Jersey to connect the New York and Erie Railroad's Piermont Branch terminus in Piermont, New York, directly to Erie's primary terminal in Jersey City, initially Exchange Place, later Pavonia Terminal. In 1870 the line was extended to Nyack, New York, and continued to provide passenger service until 1966. After the Erie's unsuccessful merger with the Lackawanna Railroad to form the Erie-Lackawanna, ownership of the line passed into the hands of Conrail upon its formation in 1976 from a number of bankrupt railroads.