A Gaeltacht (Gale-tuct) is a region of Ireland that is designated by the government as Irish speaking. There are a few of these areas, mainly along the coast, where the majority of people will conduct their daily affairs through Irish (although they're mostly happy to speak English to you if they notice you have no idea what they're saying!).

Back in the 00's an Irish heritage group in Canada bought a chunk of land in Ontario and managed to get it designated as a Gaeltacht.

So officially, as of today, Irish is the common vernacular in several small-ish regions of Ireland and a .25km^2 chunk of Canada.

Bit more info here: https://en.m.wikipedia.org/wiki/Permanent_North_American_Gae...