The Baltimore and Ohio Railroad is one of the oldest railroads in the United States and the first common carrier railroad. At first this railroad was located entirely in the state of Maryland with a line from the port of Baltimore west to Sandy Hook. At this point to continue westward, it had to cross into Virginia over the Potomac River, adjacent to the confluence of the Potomac, from there it was extended to the Ohio River at Wheeling and a few years later also to Parkersburg, West Virginia. It is now part of the CSX Transportation network, and includes the oldest operational railroad bridge in the USA, the B&O also included the Leiper Railroad, the first permanent horse-drawn railroad in the U. S. In later years, B&O advertising carried the motto, Linking 13 Great States with the Nation, the B&O Warehouse at the Camden Yards rail junction in Baltimore now dominates the view over the right-field wall at the Baltimore Orioles current home, Oriole Park at Camden Yards. At the end of 1970 B&O operated 5552 miles of road and 10449 miles of track, not including the Staten Island Rapid Transit or the Reading and its subsidiaries. The fast-growing port city of Baltimore, Maryland faced economic stagnation unless it opened routes to the western states, as New York had done with the Erie Canal in 1820. In 1827, twenty-five merchants and bankers studied the best means of restoring that portion of the Western trade which has recently been diverted from it by the introduction of steam navigation and their answer was to build a railroad—one of the first commercial lines in the world. Two men — Philip E. Thomas and George Brown — were the pioneers of the railroad and they spent the year 1826 investigating railway enterprises in England, which were at that time being tested in a comprehensive fashion as commercial ventures. Their investigation completed, they held a meeting on February 12,1827, including about twenty-five citizens. Thomas was elected as the first president and Brown the treasurer, the capital of the proposed company was fixed at five million dollars, but the B&O was initially capitalized in 1827 with a three million dollar issue of stock. Virtually every citizen of Baltimore owned a share, as the offering was oversubscribed, construction began on July 4,1828, when Charles Carroll of Carrollton did the groundbreaking. The initial tracks were built with granite stringers topped by iron rails. The first section, from Baltimore west to Ellicotts Mills, opened on May 24,1830. Developers decided to follow the Patapsco River to a point near Parrs Ridge, a later compromise allowed the two companies to share the right of way. The State of Maryland granted the B&O a charter to build a line from Baltimore to Washington, D. C. in 1831, and the Washington Branch was opened in 1835. This line joined to the mainline at Relay, Maryland, crossing the Patapsco on the Thomas Viaduct. This line was funded by the state, and was operated separately until the 1870s
Advertisement for the Baltimore and Ohio in an 1864 Baltimore city directory, promoting its repairs and reopening at one point during the war.