U.S. Route 40 (US 40) is an east–west United States Highway. As with most routes whose numbers end in a zero, US 40 once traversed the entire United States. It is one of the original 1926 U.S. Highways, and its first termini were San Francisco, California, and Atlantic City, New Jersey. In the western United States, US 40 was functionally replaced by Interstate 80 (I-80), resulting in the route being truncated multiple times. US 40 currently ends at a junction with I-80 in Silver Summit, Utah, just outside Park City.
Starting at its western terminus in Utah, US 40 crosses a total of 12 states, including Colorado, Kansas, Missouri, Illinois, Indiana, Ohio, West Virginia, Pennsylvania, Maryland, Delaware, and New Jersey. Three former and four current state capitals lie along the route. For much of its route, US 40 runs parallel to or concurrently with several major Interstate Highways: Interstate 70 from Colorado to Washington, Pennsylvania; and again from Hancock, Maryland to Baltimore, Maryland; Interstate 64 in parts of Missouri and Illinois; Interstate 68 along the Maryland Panhandle; and Interstate 95 from Baltimore to New Castle, Delaware.
The west end of U.S. Route 40 is in the U.S. state of Utah at Silver Creek Junction in Silver Summit(about 20.7 miles (33.3 km) east of Salt Lake City) with Interstate 80. From there it heads southeast through Heber City and east into Colorado on its way to the Mid-Atlantic.
U.S. Route 40 begins at I-80 at Silver Creek Junction in Silver Summit, traveling south-southeast as a full freeway in a broad valley northeast of Park City. At the south end of the valley, Jordanelle Reservoir comes into view and US-40 continues south high on the slope above its western shore while Utah State Route 248 climbs away to the east on the slope overlooking the northern shore. The freeway passes through several large cuttings in the side of the mountains that were dug when US-40 was relocated to make way for the reservoir; Utah State Route 319 provides access down the slope to a state park on the shore of the reservoir. South of the reservoir, the dam is visible on the left and the road loses elevation quickly before abruptly connecting to a (suburban or exurban) non-freeway segment with frequent curb cuts and building frontage. In central Heber, U.S. Highway 189 continues south, but US-40 turns east to leave the city. US-40 continues south and east through mountains and the Uintah Basin to the Colorado border near Dinosaur National Monument.
In the U.S. state of West Virginia, U.S. Route 40 (US 40) runs for 16 miles (26 km) through the Northern Panhandle region. The highway enters the state on the Military Order of the Purple Heart bridge concurrent with US 250, crossing Wheeling Island, before joining Interstate 70 (I-70) over the Fort Henry Bridge before leaving the interstate. The highway travels north around Wheeling Hill, before traveling through the northeastern suburbs of Wheeling, Triadelphia and Valley Grove before entering Pennsylvania. A majority of the route still follows the old National Road which predates the U.S. Highway System.
Before the construction of I-70, US 40 continued southeast along Zane Street to Virginia Street, crossing the east channel of the Ohio River on the Wheeling Suspension Bridge.
The entire route is in Ohio County.
U.S. Route 40 (US 40) is a US highway running from Park City, Utah east to Atlantic City, New Jersey. In the US state of Delaware, it serves as a major east–west highway in northern New Castle County, just south of Wilmington. It runs from the Maryland border east of Elkton, Maryland east to the Delaware Memorial Bridge over the Delaware River to New Jersey, at which point it is concurrent with Interstate 295 (I-295). Along the way, US 40 runs through suburban areas of Glasgow and Bear before following US 13 and I-295 around New Castle. US 40 is a multilane divided highway the entire length across Delaware.
US 40 was originally built as a state highway during the 1920s, comprising Elkton Road and a part of the Dupont Highway. When first designated, the route followed these two roads to Wilmington, where it crossed the Delaware River on a ferry to Penns Grove, New Jersey. By the 1930s, the route was rerouted at Hares Corner to head east into New Castle and cross the river on a ferry to Pennsville, New Jersey. Also, the entire length of US 40 west of Hares Corner was widened to a divided highway during the 1930s. The Delaware Memorial Bridge opened in 1951, and US 40 was rerouted up US 13 to the bridge approach, with Delaware Route 273 (DE 273) being extended along the former route into New Castle. In 1959, the Delaware Memorial Bridge approach became a part of I-295. Between the 1960s and 1990s, US 301 ran along the US 13/US 40 concurrency and US 301N followed US 40 between Glasgow and State Road from the 1970s to the 1980s.