I think the majority of them were made in Canada (Boler, Trillium
, and now Escape). Perhaps this stems from them being "invented" by a Canadian (Boler).
Some are made in the US now, but many of them started in Canada - for example Scamp
started by using Boler
molds, as I understand it -- perhaps to make Boler
Americans -- and many are still made in Canada.
Other US made brands were more minor and/or are out of business now (Perris/Hunter/various Boler
There are a few made in the US now (Trillium, Egg Camper), but for many years there were sooo many made in Canada.
I think only Casitas are made in the south (Texas), and they seem to be Boler clones (well, not exactly clones, but somehow related guessing by shape).
Anyway, in summary, I think it's safe to say that in the early years the vast majority were made in Canada.
PS: I have done my part, having picked up my Winnipeg-built Boler in
Winnipeg, where it lived for its first 34 years, and bringing it to the SE US