The Baltimore and Ohio Railroad (reporting marks BO, B&O) was the oldest railroad in the United States and the first steam-operated common carrier. Construction of the line began in 1828, and it operated as B&O from 1830 until 1987, when it was merged into the Chessie System. Its lines are today controlled by CSX Transportation (CSX).
Founded to serve merchants from Baltimore who wanted to do business with settlers crossing the Appalachian Mountains, the railroad competed with several existing and proposed turnpikes and canals, including the Erie and Chesapeake and Ohio Canal, and eventually with other rail networks such as the Pennsylvania Railroad. The railroad began operation in 1830 on a 13-mile line between Baltimore and Ellicott's Mill in Maryland. Horse-drawn cars were replaced by steam locomotives the following year.
Over the following decades, construction continued westward. During the American Civil War, the railroad sustained much damage but proved crucial to the Union victory. After the war, the B&O consolidated several feeder lines in Virginia and West Virginia, and expanded westward into Ohio, Indiana, and Illinois.
In 1962, the Chesapeake and Ohio Railroad gained control of the B&O, though it continued to operate separately. By 1970, the B&O operated 4,535 miles (7,300 km) of mainline track, plus the Staten Island Rapid Transit system and the Reading Railroad and its subsidiaries. The B&O ended long-distance passenger service in 1971, although it continued limited commuter service at Washington, D.C., and Pittsburgh. In 1987, the B&O was formally merged into the C&O, which was by then a subsidiary of CSX.
The B&O is noted as a pioneer in railroading. It was the first U.S. railroad to operate a steam locomotive (the Tom Thumb); it built historic infrastructure; and it operated prestigious passenger trains. It also gained fame as one of the four railroads in the original version of the board game Monopoly.
The railroad reached the Ohio River in 1852, 24 years after the project started. From the railroad's founding, one of its primary goals was to link the East Coast transportation hub of Baltimore across the Ohio River to Midwestern states. By crossing the Appalachian Mountains, a technical challenge, the railroad would link the new and booming territories of what at the time was the West, including Ohio, Indiana, and Kentucky, with the east coast rail and boat network, from Maryland northward. There was no rail link between Maryland and Virginia until the B&O opened the Harpers Ferry bridge in 1839.
Beginning in 1825, the Erie Canal provided an animal-powered water facility, connecting New York City with Ohio via Lake Erie. It took ten days to travel downstream from Buffalo, New York, to New York City. The Cumberland Road, later the beginning of the federally financed National Road, provided a road link for animal-powered transport between Cumberland, Maryland, on the Potomac River and Wheeling, Virginia, in present-day West Virginia, on the Ohio River, when it was completed in 1837. It was the second paved road in the country. However, the 1831 DeWitt Clinton locomotive, running between Albany and Schenectady, New York, demonstrated speeds of 25 miles per hour (40 km/h), dramatically decreasing the cost of transportation and announcing the coming end of the canal and turnpike (road) systems, many of which were never completed since they were or would soon be obsolete.
In New York, political support for the Erie Canal detracted from the prospect of building a railroad to replace it, whose full length did not open until 1844. Mountains in Pennsylvania made construction in the western part of the state expensive and technically challenging; the Pennsylvania Railroad, linking Pittsburgh and Philadelphia, did not open its full length until 1852, and there was no rail link west from Pittsburgh to Ohio for several more years.
The fast-growing port city of Baltimore, Maryland, faced economic stagnation unless it opened a route to the Western states. On February 27, 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". Their answer was to build a railroad: one of the first commercial lines in the world.
Their plans worked well, despite many political problems from canal backers and other railroads. Only the Pennsylvania Railroad was allowed to build in its namesake state, requiring the B&O to skirt around a corner of the state, even though the Pennsylvania Railroad didn't even operate in that area of Pennsylvania.
The railroad grew from a capital base of $3 million in 1827 (equivalent to $85 million in 2025) to a large enterprise generating $2.7 million of annual profit on its 380 miles (610 km) of track in 1854, with 19 million passenger miles. The railroad fed tens of millions of dollars of shipments to and from Baltimore and its growing hinterland to the west, thus making the city the commercial and financial capital of the region south of Philadelphia.
Although the Albany and Schenectady Railroad was chartered a year earlier, in 1826, the B & O Railroad was the first to open in the US. Philip E. Thomas and George Brown were the pioneers of the railroad. In 1826, they investigated railway enterprises in England, which were at that time being tested in a comprehensive fashion as commercial ventures. Their investigation completed, they held an organizational meeting on February 12, 1827, including about twenty-five citizens, most of whom were Baltimore merchants or bankers. Chapter 123 of the 1826 Session Laws of Maryland, passed February 28, 1827, and the Commonwealth of Virginia on March 8, 1827, chartered the Baltimore and Ohio Rail Road Company, with the task of building a railroad from the port of Baltimore west to a suitable point on the Ohio River. The railroad, formally incorporated April 24, was intended to provide a faster route for Midwestern goods to reach the East Coast than to the hugely successful but slow Erie Canal across upstate New York. Thomas was elected as the first president and Brown the treasurer. The capital of the proposed company was fixed at $5 million, but the B&O was initially capitalized in 1827 with a $3 million issue of stock. Half of this stock was reserved for the Maryland state government, which invested $1,000,000, and the municipal government of Baltimore, which invested $500,000. The remaining private equity was purchased by around 22,000 people, equivalent to one-quarter of the city's population at the time.
Early construction and legal battles
Construction began on July 4, 1828.
The initial tracks were built with granite stringers topped by strap iron rails. The first section, from Baltimore west to Ellicott's Mills (now known as Ellicott City), opened on May 24, 1830. While a steam locomotive (Tom Thumb) was demonstrated on the B&O in 1830, the railroad did not switch to steam until 1831, and the first trains on the 26-mile (42 km) round trip to Ellicott's Mills were pulled by horses.
From Ellicott's Mills, the railroad followed the Patapsco River upstream to a high point near Parr's Ridge (now known as Mount Airy), where it descended into the Monocacy and Potomac river valleys. Further extensions opened to Frederick (including the short Frederick Branch) on December 1, 1831; Point of Rocks on April 2, 1832; and Sandy Hook on December 1, 1834. Sandy Hook, on the north bank of the Potomac, remained the end of the line until 1836 when the railroad opened its bridge over the Potomac River to reach Harpers Ferry (then Virginia, now West Virginia). A connection at Harpers Ferry with the Winchester and Potomac Railroad, running southwest to Winchester, Virginia, opened in 1837.
Pushing west from Harpers Ferry, the B&O reached Martinsburg in May 1842; Hancock in June 1842; and Cumberland on November 5, 1842, which remained the end of the line for a number of years. Additional sections opened to Piedmont on July 21, 1851, and Fairmont on June 22, 1852. Later that year, the B&O finally reached the Ohio River at Moundsville, where port facilities were built, followed shortly later by Wheeling (then Virginia, now West Virginia) on January 1, 1853. Wheeling remained the terminus through the American Civil War until a bridge could be constructed across the Ohio River.