United States Numbered Highway System in the context of "U.S. Route 2"

The Dwight D. Eisenhower National System of Interstate and Defense Highways, commonly known as the Interstate Highway System, or the Eisenhower Interstate System, is a network of controlled-access highways that forms part of the National Highway System in the United States. The system extends throughout the contiguous United States and has routes in Hawaii, Alaska, and Puerto Rico.

In the 20th century, the United States Congress began funding roadways through the Federal Aid Road Act of 1916, and started an effort to construct a national road grid with the passage of the Federal Aid Highway Act of 1921. In 1926, the United States Numbered Highway System was established, creating the first national road numbering system for cross-country travel. The roads were funded and maintained by U.S. states, and there were few national standards for road design. United States Numbered Highways ranged from two-lane country roads to multi-lane freeways. After Dwight D. Eisenhower became president in 1953, his administration developed a proposal for an interstate highway system, eventually resulting in the enactment of the Federal-Aid Highway Act of 1956.

U.S. Highway 75 (US 75) is a part of the U.S. Highway System that travels from I-345 in Dallas, Texas northward to the Canadian border in Noyes, Minnesota. In the state of Texas it runs from I-345 in Dallas and heads north to the Oklahoma state line, a distance of about 75.3 miles (121.2 km).

U.S. Route 15 (US 15) is a part of the United States Numbered Highway System that runs from Walterboro, South Carolina, to Painted Post, New York. In Virginia, the U.S. Highway runs 230.37 miles (370.74 km) from the North Carolina state line near Clarksville north to the Maryland state line at the Potomac River near Lucketts. US 15 is a major north–south highway through the Piedmont of Virginia, connecting Clarksville and Farmville in Southside with Culpeper, Warrenton, and Leesburg in Northern Virginia.

Some U.S. Routes are given directional suffixes to indicate a split of the main route — for instance, U.S. Route 25 (US 25) splits into US 25E (east) and US 25W (west) between Newport, Tennessee, and North Corbin, Kentucky, and US 9W is an alternate of U.S. Route 9 between Fort Lee, New Jersey, and Albany, New York. These splits were in the U.S. Highway system from the beginning, and were used when two roughly-equivalent routes existed. The American Association of State Highway and Transportation Officials (AASHTO) no longer assigns these numbers, and, in theory, current ones are to be eliminated "as rapidly as the State Highway Department and the Standing Committee on Highways can reach agreement". This policy was adopted by 1996; however, many of these routes still exist, mostly in Tennessee.

U.S. Route 25W (US 25W) is the western branch of US 25 from Newport, Tennessee, where US 25 splits into US 25E and US 25W, to North Corbin, Kentucky, where the two highways rejoin.

US 25W has been included in the United States Numbered Highway System since the system's inception in 1926.

U.S. Route 66 or U.S. Highway 66 (US 66 or Route 66) was one of the original highways in the United States Numbered Highway System. It was established on November 11, 1926, with road signs erected the following year. The highway ran from Chicago, Illinois, through Missouri, Kansas, Oklahoma, Texas, New Mexico and Arizona before terminating in Santa Monica, California, covering a total of 2,448 miles (3,940 km).

It was recognized in popular culture by both the 1946 hit song "(Get Your Kicks on) Route 66" and the Route 66 television series, which aired on CBS from 1960 to 1964. It was also featured in the Disney/Pixar animated feature film franchise Cars, beginning in 2006. In John Steinbeck's novel The Grapes of Wrath (1939), the highway symbolizes escape, loss and the hope of a new beginning; Steinbeck dubbed it the Mother Road. Other designations and nicknames include the Will Rogers Highway and the Main Street of America, the latter nickname shared with U.S. Route 40.

U.S. Route 1 or U.S. Highway 1 (US 1) is a major north–south United States Numbered Highway that serves the East Coast of the United States. It runs 2,370 miles (3,810 km) from Key West, Florida, north to Fort Kent, Maine, at the Canadian border, making it the longest north–south road in the United States. US 1 is generally paralleled by Interstate 95 (I-95), though US 1 is significantly farther west and inland between Jacksonville, Florida, and Petersburg, Virginia, while I-95 is closer to the coastline. In contrast, US 1 in Maine is much closer to the coast than I-95, which runs farther inland than US 1. The route connects most of the major cities of the East Coast from the Southeastern United States to New England, including Miami, Jacksonville, Augusta, Columbia, Raleigh, Richmond, Washington, D.C., Baltimore, Philadelphia, Newark, New York City, New Haven, Providence, Boston, and Portland.

While US 1 is generally the easternmost of the main north–south U.S. Routes, parts of several others occupy corridors closer to the ocean. When the road system was laid out in the 1920s, US 1 was mostly assigned to the existing Atlantic Highway, which followed the Atlantic Seaboard Fall Line between the Piedmont and the Atlantic Plain north of Augusta, Georgia. At the time, the highways farther east were of lower quality and did not serve the major population centers. From Henderson, North Carolina, to Petersburg, Virginia, it is paralleled by I-85. Construction of the Interstate Highway System gradually changed the use and character of US 1, and I-95 became the major north–south East Coast highway by the late 1960s.