If I were to make a survey on the regions of the US, which regions would be a must to include?
I have recently done a survey on the regions on europe and posted the results on r/MapPorn . Now I was thinking about doing a similar one on the US. It just seems that there are a LOT of regions and subregions one could divide the US into. Of course I would include big ones like Northeast, Midwest, South and West. And then a bit more specific ones, like New England, Mid-Atlantic, South-Atlantic, Pacific, Mountain States,...
But I was also thinking about including less strictly defined regions, like Wild West or Deep South.
What would be some must haves, that I should include?
I know much less about US geography and culture than Europe, so I'm not sure which are more important or interesting.
I aim to have about 30-40 regions max.