Cascadia (bioregion)

The Cascadia bioregion is the Pacific Northwest as defined through the watersheds of the Columbia, Fraser and Snake Rivers, as defined through the geology of the region.^[1] It extends for more than 2,500 miles (4,000 km) from the Copper River in Southern Alaska, to Cape Mendocino, approximately 200 miles north of San Francisco, and east as far as the Yellowstone Caldera and continental divide and contains 75 distinct ecoregions.^[2]

The Cascadia Bioregion encompasses all of the state of Washington, all but the southeastern corner of Idaho, and portions of Oregon, California, Nevada, Utah, Wyoming, Montana, Alaska, Yukon, and British Columbia. Bioregions are geographically based areas defined by land or soil composition, watershed, climate, flora, and fauna. The Cascadia Bioregion claims the entire watershed of the Columbia River (as far as the Continental Divide), the Fraser River, as well as the Cascade Range from Northern California well into Canada. It's also considered to include the associated ocean, the Cascadia Inner Sea, and seas and their ecosystems out to the continental slope running down the entirety of the Cascadia subduction zone to the Cape Mendocino Fracture Zone.^[3] The delineation of a bioregion has environmental stewardship as its primary goal, with the belief that political boundaries should match ecological and cultural boundaries.^[4]

The area from Vancouver, B.C. down to Portland, Oregon has been termed the Cascadia Megaregion, a megaregion defined by the U.S. and Canadian governments, especially along the 'Cascadia Corridor'. Megaregions are defined as areas where "boundaries begin to blur, creating a new scale of geography now known as the megaregion. These areas have interlocking economic systems, shared natural resources, and ecosystems, and common transportation systems link these population centers together. This area contains 17% of Cascadian land mass, but more than 80% of the Cascadian population. The Canada–US border is diminishing in the face of further economic, political and cultural integration with such programs as the enhanced drivers license program – which can be used to get across the Canada–US border between Washington and British Columbia.^[5]