I seem to recall some guestimates about the number that made it to the US, but I wonder if there are any more definitive numbers of the distribution of M3Ws across the world. I'm most interested in the number in the US, and I would assume that the large majority of them stayed in the UK.

14 of them are in New Zealand

At least two in Arkansas that I know of personally

Approximately 5 in Washington State USA.

1 in Aptos, CA

I know of 3 here in Las Vegas that came from my dealer in LA. Assuming for the heck of it that there are actually twice that number, and scaling for LV's 2.6M population to the US population of 328M, that suggests a wild ass guess of about 750 in the USA.
The same math from 5 cars in Washington state, and a population of 7.6M gives a second possibility of 215 cars. Seems too low.

The Factory will probably give you the information

"The Factory will probably give you the information" - perhaps, so I'll pose the question to them!

A year or so ago, my dealer guessed at ~300 in the US.

Wishful thinking. I have had a warranty issue on a new one that they refuse to address. It is on me to transport my MOG to and from the nearest dealer since my dealer went out of business between purchase and delivery and that dealer told me they do not honor Morgans payments in full for work one because Morgan under pays them. So roughly 3,000 miles round trip and whatever Morgan West charges does not make me feel optimistic about Morgan doing anything positive for The Colonies. Maybe they are still pissed about 1776?

Well it is funny that the factory is very proud of their parts but when it comes to paying for warranty work they are pretty tight with respecting other people's labor. I will bite the bullet on this first go round. I love the car and I will do my work myself with the help of those on this valuable forum. Back to the topic of cars in the USA, there can't be many compared to the population. I have yet to meet anyone who has ever seen one of these little cars.