The Sussex Railroad was a short-line railroad in northwestern New Jersey. It replaced its predecessor, the Sussex Mine Railroad, in 1853 and operated under the Sussex Railroad Company until 1945 when it was fully merged into the Delaware, Lackawanna and Western Railroad (DL&W) system. The Sussex Railroad was important in the economic development of Sussex County as it supplied a route for early local industries, such as dairy farms and ore mines, to export their products. It was the last independently operated New Jersey railroad to be incorporated into the DL&W system. The last train travelled on the Sussex Railroad tracks on October 2, 1966. The tracks were removed soon after and the right-of-way was transformed into a rail trail known as the Sussex Branch Trail.

The Delaware, Lackawanna and Western Railroad, also known as the DL&W or Lackawanna Railroad, was a U.S. Class 1 railroad that connected Buffalo, New York, and Hoboken, New Jersey, and by ferry with New York City, a distance of 395 miles (636 km). The railroad was incorporated in Pennsylvania in 1853, and created primarily to provide a means of transport of anthracite coal from the Coal Region in Northeast Pennsylvania to large coal markets in New York City. The railroad gradually expanded both east and west, and eventually linked Buffalo with New York City.