I did a little experiment this evening (because why the hell not). I wanted to see which states Idaho is most commonly grouped with when the country is split into “regions” (because I’ve seen it put into the Pacific Northwest, the West, the North West, etc., each with different states along with it). So I went to Google Images and typed “regions of the US” to see what I could find.
I looked at 50 different maps and recorded how many times each state (apart from Idaho, of course) was grouped along with Idaho.
Results!
States like Mississippi and Louisiana and such were grouped on some map showing the nuclear regions (or something like that) of the US.
Heat map!
Heat map courtesy of here.
Interesting to see the difference in grouping frequency between our state to the east (Montana) versus the two to our west (Washington and Oregon)
Eigenblogger 
My experience has been that it largely depends on who you ask, and more importantly, what part of Idaho they are thinking of. The northern panhandle almost always gets grouped with the Pacific Northwest, Washington and Oregon, though occasionally Montana. Southern Idaho though almost always seems to be grouped with the western states, like Utah & Nevada. This is yet another example of how Idaho itself almost seems to be two separate states, split between the north and south.
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