It connects the Greenland Sea, an extension of the Arctic Ocean, to the Irminger Sea, a part of the Atlantic Ocean. It stretches 300 miles (480 km) long and 180 miles (290 km) wide at its narrowest, between Straumnes, the northwestern headland of the Westfjords peninsula of Hornstrandir, and Cape Tupinier on Blosseville Coast in East Greenland). The official International Hydrographic Organization delineation between the Arctic and the North Atlantic Oceans runs from Straumnes to Cape Nansen, 132 km southwest of Cape Tunipier. From Straumnes to Cape Nansen the distance is 336 km.
The narrow depth, where the Greenland–Iceland Rise runs along the bottom of the sea, is 625 feet. The cold East Greenland Current passes through the strait and carries icebergs south into the North Atlantic. It hosts important fisheries.
The world's largest known underwater waterfall, known as the Denmark Strait cataract, flows down the western side of the Denmark Strait.
During World War II, the Battle of the Denmark Strait took place on 24 May 1941. The German battleship Bismarck sank the British battlecruiser HMS Hood, which exploded with the loss of all but three of its 1,418 crew; HMS Prince of Wales was seriously damaged in the engagement. Bismarck entered the Atlantic through the Strait, but damage sustained in the battle—combined with British aircraft search-and-destroy missions—led to its sinking three days later.