|Land area||585.711 km2|
|On other land||1|
The Onion Lake Cree Nation is a Plains Cree First Nations band government in Canada, straddling the Alberta/Saskatchewan provincial border approximately 50 km (31 mi) north of the City of Lloydminster.
It is within Alberta's County of Vermilion River and Saskatchewan's Rural Municipality of Frenchman Butte No. 501 at the intersection of Highway 17 and Alberta Highway 641/Saskatchewan Highway 797.
The Makaoo 120 reserve is located within both provinces while the Seekaskootch 119 reserve is wholly within Saskatchewan. Both reserves once maintained separate band governments, combining to form Onion Lake in 1914. With all reserves combined, the Onion Lake Cree Nation has a total land area of 585.711 square kilometres (226.144 sq mi), and has 6,475 registered members (as of August 2019).
The Onion Lake Cree Nation has four schools within the community, one of which is a Cree immersion program.
Onion Lake is a translation of Wicekikaskosîwi-sâkahikan, "Wild Onion" smelly plant, a nearby body of water where the plant was abundant. When referring to the community today, though, Cree speakers typically use wîhcekaskosîwi-sâkahikanihk, "[domestic] onion lake".
The unincorporated area of Onion Lake is located within the Saskatchewan portion of the Onion Lake Cree Nation at the intersection of Highway 17 and Alberta Highway 641/Saskatchewan Highway 797.