Western United States

region comprising the westernmost states of the United States

The Western United States—commonly referred to as the American West or simply The West—traditionally refers to the westernmost states of the United States. As the United States has expanded westward since its founding, the definition of the West has changed over time. In the 18th and early 19th centuries the Appalachian Mountains were considered to be the boundary. Nowadays the Mississippi River is often referenced as the easternmost possible boundary of the West. The Census Bureau defines the western United States as these states:

The "West" had played a large role in American history; the American Old West is an important part of America's folklore.