Here in Massachusetts, I don't hear it often, but when I use it nobody even blinks an eye at it. It's well understood.

an aggressively progressive set of new yorkers practically bullied me into using it a decade ago over concerns of sexism so at least when talking about people in those places in tech I can't say I share your experience. lots of coastal progressives say y'all nowadays. it's "inclusive"

I also hear people say "folks" when that is also borrowed from Southern US English

I say y'all because it has one less syllable than the other options while retaining clarity

I've lived in the northeast my whole life, and I don't remember ever being surprised at the idea of someone saying it. That's at least partially because I'm just used to the idea of people I interact with potentially not being from the northeast though. Even at a young age in the suburb I grew up in (with around 25k population, so not a particularly huge one), it was pretty common to encounter people who came from other states or countries. I guess if you're from a town small enough you might not be as used to interacting with people from other places, but is that really a regional thing or just a small town thing?

Maybe surprising to hear white people saying it, but most black people (or people who grew up in predominantly black neighborhoods) throughout the US have been using it for a long time. I would assume that's a byproduct of The Great Migration.

I'm in Maine and say it all the time, but I'm definitely unusual in that regard.