northern arm of Lake Huron (Huron, Lake) in south-central Ontario, Canada, lying between the Ontario mainland (north) and the islands of Manitoulin, Cockburn, and Drummond (south). It is 120 miles (195 km) long and 1 to 20 miles (1.6 to 32 km) wide. The channel is connected on the west with St. Marys River (via St. Joseph Channel) and on the east with Georgian Bay. Many small islands lie within the channel. A road and rail bridge extends from the mainland to Great Cloche Island before crossing to Manitoulin Island at the town of Little Current.

strait linking the Irish Sea with the North Atlantic Ocean and reaching a minimum width of 13 miles (21 km) between the Mull of Kintyre (Scotland) and Torr Head (Northern Ireland). It runs northwest-southeast between Scotland and Northern Ireland and includes the larger Arran and Gigha islands and the smaller Ailsa Craig, on each of which a lighthouse is located. The Scottish coast of the channel is deeply indented by the Sound of Jura, Kibrannan Sound, and the Firth of Clyde, and the Irish coast by the Belfast Lough.