Because of competition with the C&O canal for trade with coal fields in western Maryland, the railroad could not use the C&O right-of-way. Thus, to continue westward through the Appalachian Mountains, the B&O chose to builda bridge across the Potomac(1839) atHarpers Ferry, Virginia(since 1863, West Virginia). The line continued throughVirginiato a point just west of the junction ofPatterson Creekand theNorth Branch Potomac River, where it crossed back into Maryland to reachCumberland(1842), connecting with theNational Road, the main route west. From there the B&O extended to theOhio RiveratWheeling(1853) and a few years later (1857) also toParkersburg, West Virginia(below rapids which made navigation difficult during parts of the year). It proved crucial to Union success during the American Civil War, although the conflict also caused considerable damage (and repair costs). After the war's end, the B&O consolidated several feeder lines in Virginia and West Virginia, as well as expanded westward into Ohio (including a junction at Portsmouth), Indiana, and Illinois. B&O advertising later carried the motto: "Linking 13 Great States with the Nation."
After several mergers, the B&O became part of theCSX Transportation(CSX) network. The B&O also includes theLeiper Railroad, the first permanent horse-drawn railroad in the U.S. At the end of 1970, the B&O operated 5,552 miles of road and 10,449 miles of track, not including theStaten Island Rapid Transit(SIRT) or the Reading and its subsidiaries. It includes the oldest operational railroad bridge in the United States.
Part of the B&O Railroad's immortality has come from being one of the four featured railroads on the U.S. version of the board gameMonopoly; it is the only railroad on the board that did not directly serveAtlantic City, New Jersey.