For the island in Quebec, see Island of Montreal. Canada. Montreal Island is located in Chantrey Inlet, Nunavut, Canada. The island has an area of 25 km2 (9.7 sq mi) and a perimeter of 31 km (19 mi). Sir George Back visited the island in 1834 after descending the river which now bears his name. He left a cache of supplies on the island, which was found in 1839 on a later arctic expedition by Thomas Simpson.