Strait of Canso (also Gut of Canso or Canso Strait) is a long thin channel (27 kilometers long, 3 kilometers wide) in Canada which separates Cape Breton Island from the mainland of Nova Scotia. It connects the North Atlantic ocean to Northumberland Strait. The major town on it is Port Hawkesbury, which is on the northern side about halfway along, where the Canso Causeway now crosses it.