- The Mountain states (also known as the Mountain West or the Interior West) form one of the nine geographic divisions of the United States that are officially recognized by the United States Census Bureau. It is a subregion of the Western United States.
- Western United States (Wikipedia)
The Western United States (also called the American West, the Far West, and the West) is the region comprising the westernmost U.S. states. 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.