I was wondering that myself, for example I sit here in the middle of Ohio. While I don't regularly get together with anybody, there are roughly 10 others in the area that play anglo, unfortunately most of them playing Irish music (nothing wrong with Irish music, just not my cup of tea for what I want to play). Likewise, I know of a cluster in the Cincinnati area. Once a year I know that I can see several other concertina players at the Dublin Irish festival here in town and informally talk shop. And I head out to New England in the fall when I can for the squeeze in put on by the Button Box, (which is also a good place to call in the states for instructional material). I've thought about driving down to Dan Worrel's Palestine advent held in Teas in March, but it doesn't quite fot my schedule due to work. And I saw on here that the folks in the Northwest have gotten together on a saturday. So let folks have a rough idea where you are at, and maybe you can get a sit down for some help.
Alan