U.S. Route 101 (original alignment)

U.S. Route 101 (original alignment) was the principal Pacific Coast arterial designated in the 1926 U.S. Highway System that linked major urban centers, ports, and landmarks along the West Coast from San Diego through Los Angeles, San Francisco, Portland, and terminating in Olympia. The route followed coastal corridors, bay crossings, mountain passes, and river valleys, integrating earlier auto trails and state highways, and intersecting with historic railroads, military bases, and maritime facilities. Its original alignment shaped regional development, tourism, and interstate commerce through the mid-20th century before successive realignments and freeway construction altered its course.

Route description

The original alignment traced the Pacific littoral across three states, beginning at San Diego County near Coronado and proceeding north through Los Angeles, Ventura County, and Santa Barbara County. It passed through urban centers such as Long Beach, Santa Monica, and Pasadena, then hugged the coast via Malibu, Point Mugu, and Ventura Harbor before reaching Santa Barbara. Continuing into San Luis Obispo County, the route traversed the Cuesta Grade and Morro Bay, entering Monterey County and the Monterey Peninsula at Monterey and Carmel-by-the-Sea. The alignment crossed the Golden Gate approaches and threaded through San Francisco, crossing the San Francisco–Oakland Bay Bridge era connections toward Marin County and Novato, then followed the coastal corridor through Sonoma County, Mendocino County, and Humboldt County, serving towns such as Santa Rosa, Fort Bragg, and Eureka.

Crossing into Oregon, the highway passed through Coos Bay, Florence, and Newport before reaching Lincoln City and Tillamook. The alignment entered Portland, traversing approaches near Willamette River crossings and interchanges with early iterations of Interstate 5. Proceeding into Washington, it followed the Long Beach Peninsula, skirted around Olympic National Park approaches, and terminated in Olympia, connecting to state routes and maritime links to Puget Sound ports.

History and original alignment

The highway evolved from 19th-century auto trails such as the Jefferson Highway, Lincoln Highway, and Pacific coast routes associated with the Auto Club of Southern California and the American Association of State Highway Officials. The 1926 U.S. Numbered Highway plan established the designation that consolidated state roads like State Route 2 segments and Oregon's Coast Highway. Construction projects tied to the New Deal era and agencies including the California Division of Highways, Oregon State Highway Department, and the Washington State Department of Highways upgraded timber trestles, concrete viaducts, and coastal causeways. Early engineering faced geologic challenges near San Andreas Fault, Eel River canyons, and the Santa Lucia Range, prompting structures such as the Bixby Creek Bridge, Overstreet Arch, and wooden drawbridges at harbor mouths. The original alignment incorporated ferry connections at the Golden Gate approaches, later replaced by fixed crossings designed amid debates involving the San Francisco Board of Supervisors, California Toll Bridge Authority, and preservationists from organizations like the Sierra Club.

Major intersections and termini

Major termini included the southern portal at San Diego International Airport approaches and the northern terminus at Olympia municipal connections. Key urban intersections with national and state routes included junctions with U.S. Route 66, U.S. 50 approaches, and interchanges affecting Interstate 5, Interstate 80, and I-405 feeder roads. Notable crossings and junctions occurred at the Los Angeles River, Santa Monica Freeway approaches, the Crockett industrial interchange with U.S. 40 precursors, and the Willamette River bridges near St. Johns Bridge and Marquam Bridge corridors. Ports such as Port of Los Angeles, Port of San Francisco, Port of Portland, and Port of Olympia provided maritime termini and freight interchanges.

Changes, realignments, and decommissioning

Postwar freeway expansion, accelerated by the Federal-Aid Highway Act of 1956 and regional planning by bodies including the Metropolitan Transportation Commission (San Francisco Bay Area), yielded bypasses and freeway replacements that shifted U.S. Highway designations. Segments were truncated, renumbered as State Route 1, Oregon Route 99, and various modern SR 101 iterations, while some urban segments were subsumed into Interstate corridors. Ferry crossings and trestles were replaced or abandoned after the construction of the Golden Gate Bridge, the San Francisco–Oakland Bay Bridge, and other fixed links; communities such as Crescent City and Astoria experienced alignment shifts. Preservation debates involving National Historic Preservation Act of 1966 considerations led to listing of certain bridges and alignments in state inventories, while decommissioning processes were coordinated among American Association of State Highway and Transportation Officials, state legislatures, and local agencies.

Historic landmarks and notable structures

The original alignment included engineering and cultural landmarks: the Bixby Creek Bridge on the Big Sur coast, the Golden Gate Bridge approaches and adjacent Fort Point, historic districts in San Luis Obispo County, the Carpinteria beachfront causeways, and timber trestles near Redwood National and State Parks that interfaced with early logging railroads like the Pacific Lumber Company. In Oregon, structures such as the Yaquina Bay Bridge and historic lighthouses at Heceta Head and Cape Blanco Lighthouse are associated with the route, as are Washington landmarks including the Cape Disappointment Light and maritime facilities at Ilwaco. Cultural sites along the corridor include Hearst Castle, the Carmel Mission Basilica, the Alcatraz Island vistas from route viewpoints, and municipal historic districts in Santa Barbara, Eureka, Astoria, and Port Townsend. Many alignments traverse or abut protected landscapes managed by National Park Service, California Department of Parks and Recreation, and state historic commissions, preserving an infrastructure legacy integral to West Coast transportation history.

Category:Historic U.S. Highways