Anyone practicing law in the US and Canada? Do you need dual residency in order to "article"?

Check out Miller Canfield (US law firm with a Canadian office). Its very rare to find a US attorney who has dual citizenship and has satisfied Canadian Articling requirements.

Practicing law on both sides of the US-Canadian border is essential for immigration attorneys and maybe tax attorneys. Otherwise, i dont see the value.

Canada has a dual system of laws. E.g. in the province of Quebec, a system of civil law is used. At the federal level, as well as in every province or territory except Quebec, a system of common law is used. Because of this, there are two Canadian law degrees generally in use.

The program of study for the common law LL.B. is second-entry, undergraduate, professional degree. While the degree awarded is at the first-degree level and admission may be granted to applicants with two or three years of undergraduate studies towards a degree, in practice the programme generally requires completion of a previous undergraduate degree before registration in that programme. In fact, almost all admitted law students hold at least a bachelor level degree, and a significant number hold a graduate level degree as well.

If you want to practice law in Canada, be aware that there are bar exams for each province. In addition, in order to practice law in Canada, you have to present a file to a Commitee of equivalences, and the Committee will tell you what courses you need to take in a Canadian LL.B program.

Just know that practicing in Canada is a pain in the ass for foreign lawyers.