US 20

US 20
Country	USA
Type	US
Route	20
Length mi	3365
Established	1926
Direction a	West
Terminus a	US 101 near Cannon Beach
Direction b	East
Terminus b	Massachusetts Route 2 in Boston
States	Oregon; Idaho; Wyoming; Nebraska; Iowa; Illinois; Indiana; Ohio; Pennsylvania; New York; Massachusetts

US 20 is a major east–west United States Numbered Highway traversing the northern tier of the contiguous United States. Established in 1926, it links coastal Pacific Coast access with the urban core of Boston, intersecting or paralleling historic corridors such as the Lincoln Highway and portions of the National Road. The route serves diverse landscapes from the Cascade Range through the Great Plains to the Great Lakes coast and the Appalachian Mountains foothills.

Route description

US 20 begins near Cannon Beach on the Pacific shore and proceeds east through the Willamette Valley including Portland suburbs and the Columbia River corridor, intersecting Interstate 5 and skirting the Mount Hood National Forest. Crossing into Idaho, it traverses the Snake River plain and climbs toward the Yellowstone National Park gateway near West Yellowstone (via connecting routes), passing through the timbered basins near Boise and the Sawtooth National Recreation Area. In Wyoming the highway crosses high country near Thermopolis and runs adjacent to the Yellowstone corridor before following valleys toward Casper. Entering Nebraska, US 20 parallels the North Platte River and the Scotts Bluff National Monument region, linking communities such as Gering and Chadron. Across Iowa, the road runs near the Missouri River and crosses agricultural plains, intersecting historic rail towns including Council Bluffs. In Illinois US 20 crosses the Chicago metropolitan area via northern suburbs like Waukegan and connects to Interstate 94 and Interstate 90 corridors. Through Indiana and Ohio it serves cities such as South Bend near Notre Dame and passes the industrial centers of Toledo. In Pennsylvania and New York the route parallels portions of the Erie Canal corridor and reaches suburbs of Buffalo and Rochester. In Massachusetts it continues through communities like Pittsfield and Worcester before terminating in Boston near Kenmore Square and the Charles River.

History

Designated in the original 1926 plan of the American Association of State Highway Officials, US 20 incorporated segments of earlier auto trails including the Lincoln Highway in parts of the Midwest and eastern alignments influenced by the National Old Trails Road. During the Great Depression, sections benefited from New Deal programs such as the Works Progress Administration which funded bridge and pavement projects across Nebraska and Iowa. Post-World War II expansions paralleled the development of the Interstate Highway System, notably intersecting Interstate 80 and Interstate 90; urban bypasses were constructed around Chicago suburbs and through traffic was redirected during the 1960s and 1970s highway modernization efforts. Preservation efforts in later decades saw state agencies and groups like the National Trust for Historic Preservation advocate for protecting historic bridges, roadside architecture, and segments associated with the Route 20 corridor's role in westward migration and midwestern commerce.

Major intersections

Major junctions include interchanges with Interstate 5 near Portland, Interstate 84 (U.S.) in eastern Oregon, connections to Interstate 15 corridors near the Yellowstone access, crossings of Interstate 25 in Wyoming, junctions with U.S. Route 26 and U.S. Route 30 across the Plains, overlap with Interstate 80 in parts of Nevada and Iowa (via connecting feeder routes), direct links with Interstate 74 and Interstate 65 in the Midwest near Indianapolis suburbs, intersections with Interstate 90 and Interstate 94 in the Chicago region, and eastern termini connections to Massachusetts Route 2 and urban arteries in Boston such as Beacon Street and Commonwealth Avenue.

Special routes

Numerous business routes, bypasses, and alternate alignments exist, including business loops through towns like Caldwell and Gering, bypasses around South Bend and Toledo, and historic alignments preserved as state or county roads in Massachusetts and New York. Some segments carry concurrent designations with highways such as U.S. Route 6 and U.S. Route 30, while others form scenic byways near Mount Shasta and the Finger Lakes. Preservation and tourism groups in states like Oregon and Massachusetts have promoted interpretive signage and mapped historic alignments to highlight connections with auto-travel heritage exemplified by routes like the Lincoln Highway.

Future

Planned projects include pavement rehabilitation funded by state transportation agencies such as the Oregon Department of Transportation, bridge replacements coordinated with the Federal Highway Administration, and capacity improvements near growing metropolitan areas including Boise and Chicago suburbs. Long-range regional plans by metropolitan planning organizations like the Chicago Metropolitan Agency for Planning and the Boston Region Metropolitan Planning Organization consider multimodal upgrades, safety improvements, and potential re-routing to reduce congestion while preserving historic corridor features. Environmental reviews under the National Environmental Policy Act guide major interventions across sensitive areas like the Snake River basin and riparian zones adjacent to the Great Lakes.

Cultural impact and notable landmarks

The corridor passes numerous cultural and historic sites including Fort Yellowstone approaches, Craters of the Moon National Monument and Preserve, Scotts Bluff National Monument, Covered Wagon Museum in Guernsey, and urban landmarks in Chicago and Boston such as museums and university campuses like University of Notre Dame and Worcester Polytechnic Institute. The route figures in American literature and travel writing traditions alongside works about the Oregon Trail and the auto-tourism era; museums and heritage organizations in Idaho, Iowa, and Massachusetts curate exhibits on roadside architecture, diners, and motels that grew with intercity automobile culture. Annual events and local festivals in towns along the highway celebrate agricultural heritage, railroad history, and westward migration narratives tied to corridors such as the Lincoln Highway and other early transcontinental routes.

Category:United States Numbered Highways