a border of Canada is any of the 6 mostly well defined linear features that mark the limits of her national sovereign territory & administrative jurisdiction in relation to 3 neighboring foreign countries
which are
in the shortest case France
& in 3 somewhat longer cases Denmark
& in by far the longest & most important 2 cases the united states
all 6 are shared in common with their particular foreign country & are named for it
so there is the french border & there are the danish & the American borders
& all 6 run at least partly within the sea
while only the pair that are shared with the united states are at all visibly marked in places
& run at all on dry land
where
The border which separates Canada from the United States
Canada and there is a maritime border with Russia.
The border that borders Canada is called the Canadian border.
The US has border lines WITH (not IN ) Canada.
The US-Canada border is the longest border in the world. It stretches for 8,891 km.
Mexico does not border Canada anywhere
The only land border Canada has is with the United States.
At 8891 km, the border between Canada and the USA is the longest between any two countries, but a major section of that border (with Alaska) is not contiguous with the rest. The longest contiguous section of border between two countries in the world is between Russia and Kazakhstan, at 6846 km.
Alaska borders no U.S. states, only the nation of Canada.
The national capital of Canada is Ottawa, and is not on the U.S. border, it is on the border of Ontario and Quebec.
Canada and Mexico do not border each other