The Pacific Northwest (in the United States, commonly abbreviated as PNW), sometimes referred to as Cascadia, is a geographic region in western North America bounded by the Pacific Ocean to the west and loosely, by the Rocky Mountains on the east. Though no agreed boundary exists, a common conception includes the U.S. states of Oregon and Washington and the Canadian province of British Columbia. Broader conceptions reach north into Alaska and Yukon, south into far northern California and east to the Continental Divide, thus including Idaho, Western Montana, and western Wyoming. Narrower conceptions may be limited to the northwestern US or to the coastal areas west of the Cascade and Coast mountains. The variety of definitions can be attributed to partially overlapping commonalities of the region's history, geography, society, and other factors.
The Northwest Coast is the coastal region of the Pacific Northwest and the Northwest Plateau (also commonly known as "the Interior" in British Columbia and the Inland Empire in the United States) is the inland region. The term "Pacific Northwest" should not be confused with the Northwest Territory (also known as the Great Northwest, a historical term in the United States) or the Northwest Territories of Canada.