[someone123]

I have noticed that a lot more people have modern American ancestors in Western Canada, or at least in BC and Alberta. Vancouver is something like 5-10% people who were born in the US today, while a handful of other Canadian cities are probably in the 2-5% range.

One thing to keep in mind is that if are talking about having any ancestors this is a very low bar when you consider that the US and its precursors have been settled for around 400 years now. People might have 2,000 ancestors going back to 1600 (2 parents, 4 grandparents, 8 great-grandparents... not counting inbreeding). You could have an American ancestor and be 0.05% American. I think it is almost certainly true that most Canadians have some kind of ancestor who lived in the US at one point under this definition.

There is also the question of whether an ancestor who passed through the US counts, or whether they had to be born in the US. It was common at one point, before modern immigration controls, for people to show up and bounce around North America before settling somewhere.