The Northwest Territories (NT or NWT) (French: "les Territoires du Nord-Ouest", "TNO"; Athabaskan languages: "Denendeh"; Inuinnaqtun: "Nunatsiaq"; Inuktitut: ᓄᓇᑦᓯᐊᖅ) is a territory of Canada. At a land area of approximately and a 2011 population of 41,462, it is the second-largest and the most populous of the three territories in Northern Canada. Its estimated population as of 2016 is 44,291. Yellowknife became the territorial capital in 1967, following recommendations by the Carrothers Commission. 

The Northwest Territories, a portion of the old North-West Territory, entered the Canadian Confederation on July 15, 1870, but the current borders were formed on April 1, 1999, when the territory was subdivided to create Nunavut to the east, via the "Nunavut Act" and the "Nunavut Land Claims Agreement". While Nunavut is mostly Arctic tundra, the Northwest Territories has a slightly warmer climate and is both boreal forest (taiga), and tundra, and its most northern regions form part of the Canadian Arctic Archipelago. 

The Northwest Territories are bordered by Canada's two other territories, Nunavut to the east and Yukon to the west, and by the provinces of British Columbia, Alberta, and Saskatchewan to the south. 

The name is descriptive, adopted by the British government during the colonial era to indicate where it lay in relation to Rupert's Land. It is shortened from North-Western Territory ("see" History). In Inuktitut, the Northwest Territories are referred to as ᓄᓇᑦᓯᐊᖅ ("Nunatsiaq"), "beautiful land."
When did it enter the Canadian Confederation?
entered the Canadian Confederation on July 15, 1870