Western United States

The Western United States (also called the American West, the Western States, the Far West, the Western territories, and the West) is one of the four census regions defined by the United States Census Bureau.

As American settlement in the U.S. expanded westward, the meaning of the term the West changed. Before around 1800, the crest of the Appalachian Mountains was seen as the western frontier. The frontier moved westward and eventually the lands west of the Mississippi River were considered the West.

The U.S. Census Bureau's definition of the 13 westernmost states includes the Rocky Mountains and the Great Basin to the Pacific Coast, and the mid-Pacific islands state, Hawaii. To the east of the Western United States is the Midwestern United States and the Southern United States, with Canada to the north and Mexico to the south.

The West contains several major biomes, including arid and semi-arid plateaus and plains, particularly in the American Southwest; forested mountains, including three major ranges, the Sierra Nevada, the Cascades, and Rocky Mountains; the long coastal shoreline of the Pacific Coast; and the rainforests of the Pacific Northwest.

The Western United States is the largest region of the country, covering nearly half the land area of the contiguous United States. It is also the most geographically diverse, incorporating geographic regions such as the temperate rainforests of the Northwest, the highest mountain ranges, including the Rocky Mountains, the Sierra Nevada, and the Cascade Range, numerous glaciers, and the western edge of the Great Plains. It also contains the majority of the desert areas located in the United States. The Mojave and the Great Basin deserts lie entirely within the Western region, along with parts of the Sonoran and Chihuahuan deserts (the latter extends significantly into Texas, while both extend into Mexico). Given this expansive and diverse geography it is no wonder that the region is difficult to define precisely. Sensing a possible shift in the popular understanding of the West as a region in the early 1990s, historian Walter Nugent conducted a survey of three groups of professionals with ties to the region: a large group of Western historians (187 respondents), and two smaller groups, 25 journalists and publishers and 39 Western authors. A majority of the historian respondents placed the eastern boundary of the West east of the Census definition out on the eastern edge of the Great Plains or on the Mississippi River. The survey respondents as a whole showed just how little agreement there was on the boundaries of the West.

The region is split into two smaller units or divisions, by the U.S. Census Bureau:

Other classifications distinguish between Southwest and Northwest. Arizona, New Mexico, West Texas, and the Oklahoma panhandle are typically considered to be the Southwest states. Meanwhile, the states of Montana, Idaho, Oregon, and Washington can be considered part of the Northwest or Pacific Northwest.

The term West Coast is commonly used to refer to just California, Oregon, Washington, and Alaska, whereas Hawaii is more geographically isolated from the continental U.S. and does not necessarily fit in any of these subregions.