Viscount Melville Sound, 250 mi (402 km) long and 100 mi (161 km) wide, arm of the Arctic Ocean, Northwest Territories and Nunavut, Canada, between Victoria and Prince of Wales islands on the south and Melville and Bathurst islands on the north. It is a section of the Northwest Passage. Through McClure Strait on the west it is linked with the Beaufort Sea; Barrow Strait and McClintock Channel lead east and southeast. A crossroads of arctic waterways, it is navigable only under favorable weather conditions. The western part was explored (1850–53) by Sir Robert McClure.