It was built in 1837–1838 by the Camden and Amboy Railroad, and as such is one of the oldest railway lines in the United States.

From Bordentown, New Jersey, the line followed the east bank of the Delaware River.

[3] Although the Camden and Amboy lines became part of the Pennsylvania system, formal ownership remained with the United New Jersey Railroad and Canal Company through the Penn Central merger and bankruptcy.

[6] Conrail sold the entirety of the Bordentown Secondary to NJ Transit in 1999 for $67.5 million for a planned conversion to light rail operation.

[7] The River Line began operation on March 14, 2004, using Stadler diesel-powered light rail vehicles.