The Yellowknives, Yellow Knives, Copper Indians, Red Knives or T'atsaot'ine (Dogrib: T'satsąot'ınę) are indigenous peoples of Canada, one of the five main groups of the First Nations Dene who live in the Northwest Territories. The name, which is also the source for the later community of Yellowknife, derives from the colour of the tools made from copper deposits.
The historic Yellowknives lived north and northeast of the Great Slave Lake (Tinde'e - "Great Lake") around the Yellowknife River and Yellowknife Bay (Weledeh Cho - "Inconnu River") and northward along the Coppermine River, northeast to the Back River (Thlewechodyeth or Thlew-ee-choh-desseth - "Great Fish River") and east to the Thelon River (or Akilinik). They used the major rivers of their traditional land as routes for travel and trade as far east as Hudson Bay, where early European explorers such as Samuel Hearne encountered them in the 1770s.
The Yellowknives helped lead Hearne through the Canadian Arctic tundra from Hudson Bay to the Arctic Ocean in search of the legendary copper deposits that the Yellowknives, or 'Copper Indians', had a hand in mining and trading for tools. Later European explorers who encountered and traded with Copper Indians marked on their maps the 'Yellowknife River,' which drains into Great Slave Lake from headwaters originating near the headwaters of the Coppermine River, a traditional travel corridor. In the early 1800s and 1900s, the Yellowknives were the largest and most powerful tribe in the geographic area.
The Yellowknives and the Tłı̨chǫ (Dogrib), who also lived on the north shores of Great Slave Lake, were ancestral enemies. In the 1830s it was reported that the Dogrib almost wiped out the Yellowknives, the remnants of which - although opinions vary - either scattered south of Great Slave Lake or inter-married with the Dogrib. Following the discovery of gold in the Yellowknife area, a great mix of Dogrib, Chipewyan, and remnant Yellowknife members congregated and settled in the community or within the traditional villages of Dettah or Trout Rock.