Belle Isle, Strait of, the northern entrance from the Gulf of St. Lawrence to the Atlantic Ocean, between Newfoundland and Labrador. It is about 60 miles (96 km) long and 10 to 15 miles (16 to 24 km) wide. The strait provides the shortest open sea route from North America to Europe, but is open only between June and November, and during this season icebergs are numerous. It takes its name from an imposing granite island, 700 feet (213 m) high, at the Atlantic end.