I have another query where I can list various locations in a country. Even with just a few states it finds many hundreds more who are possibly in the US, but then I have to check for false positives. e.g. I found one in 'usaquen' (Colombia), that contains 'usa'. I would guess that there could be over 300 posting in the US as many just give a city or state. It's not viable to search for two letter state abbreviations.
It's going to be hours of work to get more accurate numbers and I don't have the time right now.
This is why you need local knowledge. There will be communities that know who is around.