Lennox Passage is a navigable waterway between Cape Breton Island and Isle Madame in Nova Scotia, Canada. Small craft use the relatively protected Passage (also correctly referred to as a strait) traveling to and from St. Peters Canal at the village of St. Peter's and the Strait of Canso to avoid sailing around the east coast of Cape Breton in the open Atlantic Ocean.
The Passage is approximately 10 nautical miles (16 km) in length from MacDonalds Shoal (near Janvrin Island) to Ouetique Island near D'Escousse with depths varying from 3 to 20 metres. Initially crossed by two ferries, (one from the present location of the bridge and one from Grandique Point to Grandique Ferry), a swing bridge construction of which had begun in 1916 was completed in 1919 which was horse-operated and according to Canadian yachtsman and author Silver Donald Cameron, a former resident of D'Escousse) in his book "Wind, whales and whisky" (page 14), was powered by Stanley Forgeron's rather temperamental horse in 1967 when Farley Mowat sailed through the passage aboard Happy Adventure on his way to Expo67 connecting Isle Madame to Cape Breton.
In February 1970 following the grounding and subsequent breakup of the Liberian-registered tanker Arrow on Cerberus Rock in Chedabucto Bay and the resulting spill of 77,000 to 82,500 barrels (more than 2 million gallons) of bunker C oil, the decision was made by the Nova Scotia Government to construct two causeways between Burnt Point and Burnt Island to stop the spread of the Arrow's spilled cargo into the lucrative fishing areas of the Passage as well as the coastline to the east.