I just viewed you point of interest. There were several reasons for French Canadian leaving for the US, some linked to the 1810-1814 war, some to the 1837 rebellion, probably more through the years between 1760 and 1846 because of the lack of opened territory to new settlers, namely the numerous children of the French Canadian residents and of course, the industrialisation in the US which required a lot of labor, cheap labor then.
If you want a good start, read "Invasion of Canada - by Pierre Burton. Two tomes, very interesting. Well written.