[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.