[Pedestrian]

Originally Posted by Capsicum

Cross border cities like San Diego-Tijuana, and El Paso-Ciudad Juarez, on the southern border, or say, Detroit-Windsor and Buffalo-Niagara Falls-Toronto, or Metro Vancouver down to Seattle?

Detroit-Windsor is still the largest agglomeration I think and the fact that Anglo-Canada and the US shares a language makes the case for a stronger tie there, but then again, there may be a case for the Mexican border communities as immigration from Mexico has created ethnic communities where the Mexican-American population is larger than Canadians living in the US in absolute number.

Canada is a larger trading partner of the US than Mexico, but not by that much (China is a larger trading partner to the US than both).

From the point of view of Canada, the US is the largest trading partner by far, than any other country.

The US and adjacent Mexican border cities share 2 common languages to a much greater degree than people who don't live near them realize. Very many people on each side of the border speak the language of the other side and US dollars are commonly accepted on the Mexican side (at least of Nogales, Sonora/Arizona, the one with which I am most familiar). I live about 40 miles north of the border and even in my town Spanish speakers have no trouble using their own language in any commercial establishment.