I don't think you'll truly find that sort of ( Ideal ) US-centric server, tbh. I mean, all players from all over the world blend into all the servers. It's just a matter of whether you're willing to make a little effort to search for the kind of people you can get along with in end-game raids or content.
But with the forums, reddit and discord at hand, I don't think you'll have too much trouble with that worry.
I'll have to agree with most of the posters before me though, Elysium-pvp would be a safe bet for a really populated server.