Canada is the second-largest country in the world, so if you know that it's in the north and, um, not Russia, you stand a pretty good chance at picking it out. (Doubly so if you just know it's in the Americas.)

Now, if you asked the same about Pakistan or Nigeria (#5 and #6 in terms of population, but far smaller and with far shorter sea borders), I'd bet that far fewer people would be able to pinpoint those with the same accuracy (whether in the English-speaking world or not).