The Slate Islands archipelago is formed of two main islands, five minor islands and numerous islets located in northern Lake Superior, 10km south of the town of Terrace Bay. The islands were created by a meteorite impact which formed a crater about 32km wide. In 1985, the Ontario government established the Slate Islands as a natural environment provincial park. The islands are notable for having Ontario's largest herd of boreal woodland caribou. The total surface area is about 36km2. The nearby Leadman Group of islands 1km east is often considered part of the Slate Islands.
