America has been made of multiple, quite different, cultures from since before the American Revolution. The Pre-revolutionary differences are well detailed by David Hackett Fischer in Albion’s Seed. (TLDR: bigger differences than between France and England) The thread is picked up by Colin Woodard’s American Nations (good summary in The Independent). (TLDR: if you think those very-different colonial societies ‘just merged’, nope, they didn’t)

Woodard is a contributor here at Medium (major reason I subscribed). I’d suggest that anyone trying to understand the rural/urban political divide read his No, the Divide in American Politics Is Not Rural vs. Urban, and Here’s the Data to Prove It here at Medium.

Also have a look at his Balkanized America (also here at Medium).