I was watching a random YouTube video and the sonic boom was mentioned and the guy was saying that it couldn't possibly have been Concorde as they didn't go supersonic over land. Which is true, but they did speed up as soon as they were far enough from land for it to be a distant (and therefore quieter) boom. I used to hear it in my childhood when I was on holiday in Kerry. The video was specifically about a place in the west of Newfoundland so I think it's quite likely that they might have heard the boom there.
Anyway, it got me thinking that I'd never thought about how rare it might be to have heard a sonic boom. Where have other people heard it?