For your reference, from your neighbours to the north:
British Columbians/Britanno-colombiens
Albertans/Albertains
Saskatchewanians/Saskatchewannais
Manitobans/Manitobains
Ontarians/Ontariens
Quebecers/Québécois*
New Brunswickers/Néo-Brunswickois
Nova Scotians/Néo-Écossais
Prince Edward Islanders/Prince-Édouardiens
Newfoundlanders and Labradorians/Terreneuviens et Labradoriens
Yukoners/Yukonnais
Nunavummiut/Britanno-colombiens
As for the Northwest Territories, I don’t think anyone is quite sure – I’ve seen “Northwest Territorian,” “Northwest Territorial,” “Northwesterner,” and “Northerner” (which last seem a trifle unspecific). If Ginger or Miss Magic8Ball could help, it’d be appreciated. In French, the term is the refreshingly definitive Ténois, from the abbreviation T.N.-O. for Territoires du Nord-Ouest.
*In English, “Québécois” is used for a French-Canadian resident of Quebec, whereas a Quebecer is any resident. In French, Québécois can be used for any resident. I’m not Québécois, mais je suis certainement Québécois.