The Newkirk Viaduct Monument was erected in 1839 in present-day Philadelphia, Pennsylvania, by the Philadelphia, Wilmington and Baltimore Railroad to mark the 1838 completion of the Newkirk Viaduct, also called the Gray's Ferry Bridge, over the Schuylkill River. The bridge completed the first direct rail line between Philadelphia and Baltimore, Maryland — tracks that closely paralled the King's Highway, the main land route to the southern states.