>"Most US states are culturally and historically insignificant." //
Someone said upthread.
Thing is they're not culturally insignificant, I've no idea where Idaho is (NW?) but somewhere I've heard about its potatoes! That's because in the UK almost all the TV is from USA. Perhaps someone in a film, cartoon series, TV serial, song was from Idaho, maybe a country singer sang about it.
That said, the impression as a European is primarily one of homogeneous culture, and primarily of European immigrants (though I'd say this is changing), particularly that Spanish speaking USA is making more impact in UK the last decade.
Generalising the UK impression is that French, Spanish, Italian, etc., are distinctive (and in stereotype monocultural) in the same way USA-ian (which most just call "American") is.
Yes, the differences of Silicon Valley/LA/Cali vs. the mountains of the Wild North, vs Washington, vs the Deep South, vs swampy Florida, etc. stand out. But the impression I, at least, get in movies is of no more variance across USA than within a Euro country.
My wife and I did a test and could name all but one of the US states (with no prep) but not all the UK counties.
There's a movie trope of kids learning the positions, shapes, State flowers, etc., of all the USA states ... I must have seen that at least 20 times in movies/TV. Never once have I seen anything approaching that for any other country (not even my own whilst I was at school).
I have absolutely no idea what the official flower of any state is, including the state where I was born, and the one I live now.
For example, when I was in China, people asked me all sorts of questions about Texas. It turns out the Lone Stars have built quite an international reputation as a... libertarian paradise. Hawaii, California and New York play on the international stage, but nobody has heard of Idaho.
Americans know the divisions of the UK. They might know Holland is a part of the Netherlands. Most of us know Bordeaux Normandy and Champagne are provinces of France, Bavaria is in southern Germany and Crimea is supposed to be in Ukraine. We know Venice, Sicily, Kashmir, Tibet, Manchuria, Xinjiang, Siberia, Baja California, the Yucatan and Patagonia.
Also our states don’t get redistricted often (ever), unlike some countries.