a channel separating Cape Breton Island from the Nova Scotia, Canada, mainland, leading from Chedabucto Bay (an inlet of the Atlantic Ocean) to St. Georges Bay and the Northumberland Strait. It is about 17 miles (27 km) long and averages 2 miles (3 km) in width, with depths of more than 200 feet (60 m). Since 1955 the 7,000-foot (2,100-metre) Canso Causeway, carrying rail and Trans-Canada Highway traffic, has linked Cape Breton Island with the mainland; a navigation lock is capable of handling most oceangoing vessels. Chief towns on the strait are Port Hawkesbury and Mulgrave. Canso is derived from the Mi'kmaq Indian kamsok, translated as “beyond the cliffs,” referring to the bluffs along the south shores of Chedabucto Bay that run eastward to Cape Canso.