Thaidene Nëné National Park Reserve, National park reserve at East Arm of Great Slave Lake, Canada.

Thaidene Nëné is a national park reserve located on the East Arm of Great Slave Lake in the Northwest Territories of Canada. The land covers boreal forest, open tundra, and deep freshwater lakes bordered by walls of red granite.

The reserve was formally created in 2019 after many years of talks between the Canadian government and Indigenous communities. The Łutsël K'é Dene First Nation played a central role in shaping how the protected area would be governed.

The Chipewyan name Thaidene Nëné means "land of our ancestors" and was chosen by the Łutsël K'é Dene First Nation. The protected area is part of the Thaidene Nëné Indigenous Protected Area, which also includes a territorial protected area and a wildlife conservation area run by the Northwest Territories government. The Łutsël K'é Dene First Nation, Deninu K'ue First Nation and Yellowknives Dene First Nation signed the 2019 agreement with Parks Canada and the territorial government.

The reserve has no road access, so most visitors fly from Yellowknife to the community of Lutsel K'e to reach it. From there, local guides can arrange fishing, paddling, and camping trips into the park.

Great Slave Lake is one of the deepest lakes in North America, and some of its deepest points fall within the reserve. This depth creates conditions where giant lake trout live far below the surface in water that stays very cold year round.