The National Road, also known as the Cumberland Road, was the first major improved highway in the United States, built by the federal government, constructed between 1811 to 1837, and which connected the Potomac River and the Ohio River. After a financial panic in 1837, construction stopped at Vandalia, Illinois, the then-capital of the state, and 63 miles short of St. Louis, Missouri on the Mississippi River.

This road was a main transport path to the West for thousands of settlers. In the 1900s, the National Road was connected with other historic routes which eventually routed to California.

In 1976, the American Society of Civil Engineers designated the National Road as a National Historic Civil Engineering Landmark. In 2002, the entire road, including extensions east to Baltimore and west to St. Louis, was designated the Historic National Road, an All-American Road.

In 1751, the Ohio Company opened the Braddock Road, a road which left the most western limit of navigation on the upper Potomac River and continue west afield to Fort Cumberland and then later, north to Fort Duquesne on the Ohio River, the present day location of Pittsburg, Pennsylvania.

This roadpath was the vision of George Washington, championed by Thomas Jefferson and authorized by Congress on 29 March 1806 to build a roadpath which would replace the wagon and footpaths of the Braddock Road to provide travel between the Potomac River and the Ohio River.

Actual construction work began in the summer of 1811 at the later to be called Zero Mile Marker. The new roadpath followed the same same alignment of the Braddock Road until arriving at Uniontown, Pennsylvania. From this location, the Cumberland Road would depart from the Braddock Road, and instead continue west to Wheeling Virginia, now in the state of West Virginia, which is a city also on the Ohio River.

National Pike, US Alt 40,

National Pike, Summit Inn 2424 feet

The National Road originated at the head of navigation on the Potomac River in Cumberland, Maryland and traversed westward across following states:

Maryland

Pennsylvania

West Virginia

Ohio

Indianna

Illinois

It was not until the early 1900s that the National Road was connected with other historic routes and in doing so, made the highway traverse across the continent to form a transcontinental highway. It was to be 3096 miles and much of the route would follow the Old National Road, the Santa Fe Trail and later the western portion of US Route 66.

At that time, the National Old Trails Road Association was formed in Kansas City in April 1912 to promote improvement of a transcontinental road form Baltimore to Los Angeles, with branches to New York City in the east and San Francisco in the west. Thus this new highway became the National Old Trails Road, which would cross North America and become part of the National Auto Trail system.

In 1926, Harry S. Truman became president of the National Old Trails Road Association and during the next year, this new highway had reached 800 miles of paved roadway. Much more of the roadway during the 1920s was oiled by a new process that was to become the forerunner of asphalt. Also, in 1926, the section west of Las Vegas to Los Angeles was certified as US 66, now known as US Route 66.

The US Highway 40 or US Route 40 shares the nickname Main Street of America with US Route 66. US 40 is a major east-west United States federal highway and as most US federal highways whose numbers ends with a zero, US 40 once traveled the entire United States coast to coast. It is one of the very first federal highways created in 1926 with its original termini in San Francisco on the west coast and Atlantic City, New Jersey on the east coast.

Currently, the west terminus is south of Salt Lake City at its junction with IH 80. West of this junction, US 40 have been functionally replace with the interstate highway, which as IH 80 was built, it truncated US 40 several times.

Currently, US highway 40 crosses: Utah, Colorado, Kansas, Missouri, Illinois, Indiana, Ohio, West Virginia, Pennsylvania, Maryland, Delaware and New Jersey, but before it was replaced with IH 80, it also crossed Nevada and California.

Originally built over several older roadpaths including the National Road (see above)an the Victory Highway, which was designated to the World War I veterans and traversed from Kansas City, Missouri to San Francisco. Also included was the Lincoln Highway throughout most of California.

Before the creation of the Interstate Highway system, which was signed by President Eisenhower on 29 June 1956, US highway 50, created in 1926 as part of the original US Highway system was planned to traverse from Annapolis Maryland to Wadsworth, Nevada along several auto trails including National Old Trails Road, the Midland Trail and the Lincoln Highway.

The western part of the route in the United States crosses mostly desert and mountains, with the section that crosses Nevada also known as The Loneliest Road in America. In the Midwest, US 50 traverses rural areas and farmland but does go through several larger cities including Kansas City, St. Louis, and Cincinnati.

The US 50 route continues into the Appalachian Mountains in West Virginia and then takes a bee line to Washington DC, after which the route continues through Maryland, crosses the Chesapeake Bay Bridge and then down to Ocean City, Maryland.

Signs at either end indicate the length is just under 3100 miles, but due to a few realignments, the route now stands at 3019 miles. Currently, US 50 passes through 12 states including: California, Nevada, Utah, Colorado, Kansas, Missouri, Illinois, Indiana, Ohio, West Virginia, Virginia, Maryland as well as the District of Columbia.