western arm of Baffin Bay (an inlet of the North Atlantic Ocean), in north-central Baffin region, Nunavut territory, Canada. The sound is 200 miles (320 km) long and 40 miles (64 km) wide. It extends between Devon Island (north) and Baffin Island (south) and joins the Barrow Strait northeast of Somerset Island. All feasible routes of the Northwest Passage, a seaway through the Canadian Arctic Archipelago connecting the Atlantic and Pacific oceans, pass through the sound. It was discovered in 1616 by William Baffin (Baffin, William), the English navigator, who named the sound for the promoter of his expedition, Sir James Lancaster (Lancaster, Sir James).