Cascadia (bioregion)
The Cascadia bioregion is a bioregion located near the Pacific Northwest as defined through the watersheds of the Columbia, Fraser, Snake, and Klamath rivers, as defined through the geology of the region. It extends for more than 2,500 miles (4,000 kilometres) from the Copper River in Southern Alaska, to Cape Mendocino, approximately 200 miles (300 kilometres) north of San Francisco, and east as far as the Yellowstone Caldera and continental divide and contains 75 distinct ecoregions.