Constance Lake First Nation is an Oji-Cree First Nations band government located on the shores of Constance Lake near HearstCochrane District in northeastern Ontario, Canada, It is directly north of the community of along a continuation of Ontario Highway 663. Constance Lake First Nation is home to close to 1605 members of Cree and Ojibway ancestry with approximately 820 living on reserve. The reserves, Constance Lake 92 and English River 66, total 7686 acres in size.
The Constance Lake First Nation members are of "Cree, Oji-Cree and Ojibway descent. Our ancestors inhabited the Kenogami, Kabinakagami, Nagagamisis, Nagagami, Pagwachuan, Fushimi, Pledger Lake, Little Current, Drowning, Ridge, Albany, Kabinakagami, Nagagami and Shekak River systems since in time of memorial in the eighteen hundreds and early nineteen hundreds." Mammamattawa (English River), where the Kenogami River joins with the Kabinakagami and Nagagami Rivers, was the site of Hudson’s Bay Company and rival Revillon Frères fur trading posts. This area became the Mammamattawa (English River) Reserve which was renamed the Constance Lake First Nation (CLFN).
Constance Lake First Nation were known as the English River Band of Oji-Cree. Prior to Treaty 9, according to a 1901 Canadian census, there were 85 people inhabiting the English River area, 60 miles inland from the mouth of the Kenogami or English River. On 27 July 1905 English River Band of Oji-Cree were attached to Treaty 9 as a subdivision of the Fort Albany First Nation on James Bay, and therefore Treaty beneficiaries. The English River band were given their own 12 square miles reserve, "[o]n the Kenogami or English River in the Province of Ontario, beginning at a point three miles below Hudson Bay Post on the North side of the River known as English River then north a portage of 3 miles and of sufficient depth to provide 1 square mile for each family of five upon the ascertained population of the band" by Treaty 9 in 1905.: