Some of the nation's earliest efforts toward the development of a reliable transportation system began in Maryland. In 1695, a public postal road was opened from the Potomac River through Annapolis and the Eastern Shore to Philadelphia. Construction on the National Road (now US 40) began at Cumberland in 1811; within seven years, the road was a conduit for settlers in Ohio. The first commercial steamboat service from Baltimore started in 1813, and steamboats were active all along the Chesapeake during the 1800s. The Delaware and Chesapeake Canal, linking Chesapeake Bay and the Delaware River, opened in 1829.
Maryland's first railroad, the Baltimore and Ohio (B&O), was started in 1828; in 1835, it provided the first passenger train service to Washington, DC, and Harpers Ferry, Virginia (now West Virginia). By 1857, the line was extended to St. Louis, and its freight capacity helped build Baltimore into a major center of commerce. In the 1850s, the Pennsylvania Railroad began to buy up small Maryland lines and provide direct service to northern cities.
Today Consolidated Rail, CSX Transportation, and Norfolk Southern are the Class I railroads operating in the state, along with one regional, one Canadian, four Local, and two switching and terminal railroads. As of 2000, total rail miles in Maryland amounted to 1,235 mi (1,987 km), including about 835 mi (1,343 km) of Class I track. The Maryland Transportation Department's Railroad Administration subsidizes four commuter lines, as well as freight lines in western Maryland and on the Eastern Shore. Amtrak operated six stations and about 70 daily trains on 94 mi (151 km) of track through the state in 1998.
The Maryland Mass Transit Administration inaugurated Baltimore's first subway line on 21 November 1983. The combined underground-elevated line ran for 8 mi (13 km) from downtown Baltimore to Reisterstown Plaza; later, the Baltimore Metro was extended for 6 mi (10 km) to Owings Mills, just outside the city limits. The Metro cost nearly $1 billion to build. In 1984, the Washington, DC, mass transit system was extended to the Maryland suburbs, including Bethesda and Rockville.
About half of Maryland's roads serve metropolitan Baltimore and Washington. As of 2000, there were 30,494 mi (49,075 km) of public roadway. The major toll road is the John F. Kennedy Memorial Highway (I-95), linking Baltimore with Wilmington, Delaware, and the New Jersey Turnpike. There were 3,382,451 licensed drivers and 3,847,538 motor vehicles registered in Maryland in 2000.
The Port of Baltimore handled 37.2 million tons of cargo in 2000, including 23 million tons of foreign cargo and 14.2 million tons of domestic cargo. There are 155 airports in Maryland. The Department of Transportation operates Baltimore-Washington International (BWI) Airport, the major air terminal in the state. Another 71 airfields (64 heliports, 1 stolport, and 6 seaplane bases) also served the state in 2002.