Wunnumin Lake First Nation (Oji-Cree language: ᐊᐧᓇᒪᐣᓵᑲᐦᐃᑲᓃᕽ (Wanaman-zaaga'iganiing, "At Wunnumin Lake"); unpointed: ᐊᐧᓇᒪᐣᓴᑲᐃᑲᓂᐠ) is an Oji-Cree First Nation band government who inhabit 360 km northeast of Sioux Lookout in Ontario, Canada. Its registered population in January 2007 was 565.
Wunnumin Lake First Nation can be accessed primarily through air transportation; however, during the winter season, one can also travel to this community using the winter roads, The White Highway. It consists of two reserves, their main reserve Wunnumin 1 and the nearby Wunnumin 2.
Wunnumin Lake is policed by the Nishnawbe-Aski Police Service, an Aboriginal-based service.
Wunnumin Lake is called Wanaman-zaaga'igan meaning "Vermillion Lake", in reference to the vermillion-coloured clay about the lake. Legend says that Wiisagejaak (the "Crane manidoo") used to hunt for food, found "Big Beaver" that lived on the Pipestone River and chased "Big Beaver" and its baby beaver to this area. When Wiisagejaak caught up with "Big Beaver" and its baby beaver, he killed the baby beaver and put it aside in this particular area with foliage; as the baby beaver laid there in this foliage, it bled from its wound. The blood from the baby beaver's wound seeped into the ground, staining the clay to this colour.
Residents of Wunnumin Lake originated from Big Beaver House, Ontario. After a large forest fire, the community at Big Beaver House relocated to two separate location, of which one was Wunnumin Lake. During 1929–1930 the leaders of Wunnumin Lake First Nation were summoned to Big Trout Lake to participate in the signing of the adhesion to Treaty 9. Its current government obtained their Reserve status on March 2, 1976.