Pacific Coast of the United States

Pacific Coast of the United States
Name	Pacific Coast of the United States
Caption	Map of the West Coast of the United States and principal cities
Length km	5500
Countries	United States
States	California, Oregon, Washington, Alaska (southern panhandle often linked culturally), Hawaii (Pacific state, non-contiguous)

Contents

Pacific Coast of the United States is the western seaboard of the United States bordering the Pacific Ocean. It includes the coasts of California, Oregon, and Washington, and is closely associated with the maritime regions of Alaska and Hawaii in cultural and economic contexts. The coast hosts major urban centers such as Los Angeles, San Francisco, San Diego, Portland, Oregon, and Seattle, and encompasses diverse landforms from the Channel Islands to the Olympic Peninsula.

Geography and Extent

The coastline extends from the international boundary with Mexico at Tijuana and Baja California north past Point Reyes, Cape Mendocino, Coos Bay, Cape Blanco, Neah Bay, and the Strait of Juan de Fuca to the Canada–United States border near Vancouver Island and British Columbia. Major coastal features include the Los Angeles Basin, the Central Coast of California, the Salish Sea, the Puget Sound, the San Francisco Bay Area, and the Santa Barbara Channel. Offshore archipelagos and banks such as the Channel Islands National Park, the Farallon Islands, the Pribilof Islands (Alaska connection), and the Hawaiian Islands chain influence regional geography. The Pacific Coast contains coastal ranges including the Sierra Nevada foothills, the Coast Ranges (California), the Cascade Range, and the Olympic Mountains, and borders major river mouths like the Sacramento River, San Joaquin River, Columbia River, and Skagit River.

The coast is shaped by plate tectonics at the Pacific Plate–North American Plate boundary, including the San Andreas Fault, the Cascadia subduction zone, and numerous transform faults and thrust systems. Volcanic features associated with the Cascade Volcanic Arc such as Mount St. Helens, Mount Rainier, Mount Hood, and Lassen Peak contrast with the granitic exposures of the Sierra Nevada batholith and metamorphic belts of the Coast Ranges (California). Offshore, features include the Continental Shelf (North America), submarine canyons like Monterey Canyon, and abyssal plains. Oceanographic processes driven by the California Current, North Pacific Gyre, upwelling along the Eel River and Cascadia shelves, and seasonal shifts in El Niño–Southern Oscillation influence sea surface temperature, nutrient regimes, and marine productivity, affecting habitats from kelp forests to deep-sea coral communities.

Climates range from Mediterranean in Southern California and the Central Valley margins, to temperate rainforest on the Olympic Peninsula and coastal Washington (state), to subarctic in southeast Alaska coastal zones. Vegetation communities include coastal sage scrub near Los Angeles, chaparral on the Peninsular Ranges, coastal redwood groves in Mendocino County and Humboldt County, Douglas fir forests in Oregon and Washington, and intertidal biomes with eelgrass beds and bull kelp forests. Faunal assemblages host species protected under statutes such as the Endangered Species Act, including California condor recoveries, southern sea otter populations, Steller sea lion rookeries, gray whale migratory corridors, humpback whale feeding grounds, Pacific salmon runs (e.g., Chinook salmon), and diverse seabird colonies like those on the Farallon Islands and Tatoosh Island.

Coastal regions were inhabited for millennia by Indigenous nations, including the Chumash, Tongva, Ohlone, Miwok, Miwok (Coast Miwok), Yurok, Hupa, Karuk, Tolowa, Yakama, Tillamook, Coast Salish peoples (e.g., Duwamish, Suquamish, Puyallup), and Tlingit and Haida groups in Alaska. European contact began with expeditions by Juan Rodríguez Cabrillo, Sir Francis Drake, and later James Cook, followed by colonization periods involving the Spanish Empire and the Russian Empire. Treaties and conflicts include the Adams–Onís Treaty context, the Oregon Treaty, and numerous local treaties and removals during the 19th century. Coastal industries altered Indigenous lifeways through missions such as Mission San Buenaventura and economic ventures like the California Gold Rush, while legal frameworks like the Marshall Trilogy and later Indian Reorganization Act affected tribal sovereignty.

The Pacific Coast supports major commercial centers including the Port of Los Angeles, Port of Long Beach, Port of Oakland, Port of San Diego, Port of Seattle, and Port of Tacoma, which together handle container traffic, bulk commodities, and trans-Pacific trade with partners such as China, Japan, South Korea, and Taiwan. Fisheries target species managed by agencies like the National Oceanic and Atmospheric Administration and the Pacific Fishery Management Council and include commercial harvests of Dungeness crab, Pacific hake, and various salmon species. Energy infrastructure includes offshore petroleum activities historically in the Santa Barbara Channel and renewable projects such as proposed offshore wind leases reviewed under the Bureau of Ocean Energy Management. Tourism economies hinge on attractions like Yosemite National Park (gateway impacts), Golden Gate Bridge, Big Sur, Disneyland, Alcatraz Island, and coastal recreation in Mendocino, Cannon Beach, and La Jolla.

Major transportation corridors include Interstate 5, U.S. Route 101, Interstate 10 west termini, and rail links operated by Union Pacific Railroad and BNSF Railway serving port complexes. Aviation hubs include Los Angeles International Airport, San Francisco International Airport, Seattle–Tacoma International Airport, and regional airports. Coastal management agencies and frameworks involve the California Coastal Commission, state parks systems like California State Parks, Oregon Parks and Recreation Department, and federal entities such as the National Park Service managing units like Point Reyes National Seashore and Olympic National Park. Coastal zoning, shoreline armoring, and sediment management intersect with law and policy instruments including the Coastal Zone Management Act.

Challenges include sea level rise driven by climate change, coastal erosion at sites like Big Sur and Point Reyes, ocean acidification impacting shellfish industries in Hatcheries and estuaries, harmful algal blooms such as Pseudo-nitzschia events affecting fisheries, and pollution incidents exemplified by the Exxon Valdez context informing regional planning. Conservation efforts are conducted by organizations including the Nature Conservancy, Audubon Society, Surfrider Foundation, and government programs such as the National Marine Fisheries Service and U.S. Fish and Wildlife Service, focusing on marine protected areas like the Channel Islands National Marine Sanctuary, habitat restoration in estuaries like the San Francisco Bay Estuary, and endangered species recovery programs for California condor and steelhead trout. Collaborative regional initiatives include cross-border programs with Mexico (e.g., Binational San Diego–Tijuana efforts) and transstate planning under entities such as the Pacific Coast Collaborative.