Seven States Border the Rocky Mountain States Region

The Rocky Mountain States (typically ID, MT, WY, UT, CO, NM, AZ) are bordered on their eastern flank by seven Great Plains states:

1. North Dakota
2. South Dakota
3. Nebraska
4. Kansas
5. Oklahoma
6. Texas
7. New Mexico (also a Rocky Mountain state itself, but its eastern plains border the others)

These seven form the transition zone from the High Plains to the Rockies' front ranges. The border is loosely defined by the 100th meridian (aridity line) and the rise of the Front Range.

Note: Some definitions include NV as a Rocky Mountain state; others exclude AZ. The seven border states remain consistent for the core Rockies.