Question about eShop cards and regions

Hello there. My friend's birthday is in a couple days and I was thinking I could get him an eShop card for the Wii U. The problem is, I'm in the U.S and he's in Canada. I don't know if the two countries are considered the same region or if a card bought here in the US would be compatible with his Canadian Wii U. I would much appreciate some assistance on this.