Original: The West can be divided into the Pacific States; Alaska, California, Hawaii, Oregon, and Washington, with the term West Coast usually restricted to just California, Oregon, and Washington, and the Mountain States, always Arizona, Colorado, Idaho, Montana, Nevada, New Mexico, Utah, and Wyoming.
Simplified: The Census Bureau defines the western United States as these 13 states: Alaska, Arizona, California, Colorado, Hawaii, Idaho, Montana, Nevada,New Mexico,Oregon, Utah, Washington, and Wyoming.