When was the last time the Canada–US border closed to visitors?

Question

Multiple sources have reported that Canada and the United States have announced that the Canada–United States border is about to close to non-essential travel in an effort to reduce the spread of Covid-19. For example, see https://www.cnn.com/travel/article/essential-travel-coronavirus/index.html

"Well I think essential is medical, we have military working together, we have industry working together, and again, it's not affecting trade, so things like that," said President Trump. "But just leisurely 'let's go to a restaurant and have dinner,' which a lot of people do ... we have ended on a temporary basis."

When was the last time either Canada or the US banned citizens or residents of the other from visiting for tourism or other non-essential purposes? My guess is the War of 1812, but I can't seem to find the answer online.

Answer 1

Never. Only in the early wars between France and England, but then it didn’t mind whether the enemies were in which territory and the border were unclear and the definition of the border was the cause of the war.

How would they have been able to

a) control a border that was the longest of the world

b) of two countries that haven’t been fully explored

c) and the border wasn’t clearly defined.

even not 1850.

https://en.wikipedia.org/wiki/Pig_War_(1859)

And what sense would it make to close a border of 2 countries if you can’t control it as there are so few inhabitants like in Montana, Idaho, Wyoming etc?

Even today it must be rather a symbolic gesture to close the border: Highways, Railway, Airports.

https://www.cgpgrey.com/blog/canada-the-united-states-bizarre-borders-part-2