I had to look this up: the Northwest Territories are a part of Canada. It's only mentioned about half way through the article.
As a Canadian, this is how I feel whenever folks are talking about US states other than like, Texas or New York. It's interesting being in Europe or somewhere and having a bunch of travelers introduce themselves, I've always noticed that most people will say what country their from, Italy, France, Canada etc, but Americans always just use their state.
Interesting topic. In Europe it seems by country. From France vs from Paris