When & where did the term Canuck originate and why?

Answer 1

The use of "Canuck" by Canadians themselves is usually affectionate or patriotic.

The term was coined in the 19th century, although its etymology is unclear.

Answer 2

Way back in the day, English Colonists used to call French colonists Canucks... I don't really knwo why, but I think it has something to do with les Canadiens assimilating into Algonkin culture.
The name has since stuck, and like all Americans get called Yankees around the world, we get calle Canucks, even though it was a term that described les Quebecois.