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 .