The Diocese of Algoma is a diocese of the Ecclesiastical Province of Ontario of the Anglican Church of Canada. It comprises nearly 182,000 square kilometres of the Ontario districts of Algoma (from which it takes its name), Thunder Bay, Sudbury, Manitoulin, and parts of the districts of Nipissing and Timiskaming. The diocese forms a wide band stretching from just west of Thunder Bay on the northern shore of Lake Superior east to the border of Ontario and Quebec.