U.S. Route 6 (US 6), also called the Grand Army of the Republic Highway, honoring the American Civil War veterans association, is a main route of the U.S. Highway system. While it currently runs east-northeast from Bishop, California to Provincetown, Massachusetts, the route has been modified several times. The highway's longest-lasting routing, from 1936 to 1964, had its western terminus at Long Beach, California. During this time, US 6 was the longest highway in the country.
In 1964, the state of California renumbered its highways, and most of the route within California was transferred to other highways. This dropped the highway's length below that of US 20.
US 6 is a diagonal route, whose number is out of sequence with the rest of the U.S. Highway grid in the western US. When it was designated in 1926, US 6 only ran east of Erie, Pennsylvania. Subsequent extensions, largely replacing the former U.S. Route 32 (US 32) and U.S. Route 38 (US 38), have taken it south of US 30 near Chicago, Illinois, US 40 near Denver, Colorado (past the end of US 38), US 50 at Ely, Nevada, and even US 70 near Los Angeles, California, due to its north–south alignment in that state.
In the U.S. State of Nebraska, U.S. Highway 6 is a highway which goes from the Colorado border west of Imperial in the west to the Iowa border in the east at Omaha. Significant portions of the highway are concurrent with other highways, most significantly, U.S. Highway 34 between Culbertson and Hastings. Also, from Milford east to the Iowa border, the highway is closely paralleled by Interstate 80.
U.S. Highway 6 enters Nebraska from Colorado west of Imperial on a short southeasterly segment. It turns east and stays due east until shortly before Imperial. It then goes into Imperial and meets Nebraska Highway 61. The two routes are paired together until they separate at the Enders Reservoir State Recreation Area. It goes in a generally southeasterly direction until it meets U.S. Highway 34 west of Culbertson.
US 6 and US 34 continue east together through Culbertson and at McCook, is briefly concurrent with U.S. Highway 83. US 6/34 continue together in a northeasterly direction through Cambridge, then turns due east and meets U.S. Highway 283 in Arapahoe. Near Edison, it meets U.S. Highway 136, which begins at its intersection with US 6/34. Further east, the two highways meet Nebraska Highway 4 and turns northeast towards Holdrege, Nebraska. In Holdrege, US 6/34 meet U.S. Highway 183. The highways continue on a northeasterly trajectory through Minden until Heartwell. At Heartwell, US 6/34 turns due east until Hastings. In Hastings, US 6/34 meet U.S. Highway 281 and US 34 separates to go with US 281 while US 6 continues eastward.
U.S. Route 6 (US-6) is a major east–west state highway through the central part of the U.S. state of Utah. Although it is about 40 miles (64 km) longer than US-50, it serves more populated areas, and in fact follows what had been US-50's routing until it was moved to follow Interstate 70 (I-70) in 1976. In 2009, the Utah State Legislature named part of the route the Mike Dmitrich Highway, which generated controversy, as the state of Utah had previously joined with all the other states through which US-6 passes in naming all of US-6 the Grand Army of the Republic highway.
US-6 enters Utah overlapped with US-50 in the Great Basin, a large desert that includes much of western Utah. As part of the Basin and Range Province, the terrain alternates between north–south oriented flat valleys and mountain ranges. US-6 and US-50 cross the Snake Valley, Confusion Range (through Kings Canyon), Tule Valley, House Range (via Skull Rock Pass), and Pahvant Valley (passing north of Sevier Lake), finally reaching the town of Hinckley just before they split in Delta. US-6 turns to the northeast at that city, paralleling the Union Pacific Railroad's Lynndyl Subdivision to the west of the Canyon Mountains, Gilson Mountains, and East Tintic Mountains—three ranges that form the eastern boundary of the Basin and Range Province.