English Channel, an arm of the Atlantic Ocean between England and France. It is about 350 miles (560 km) long and joins the North Sea at the east end of the Strait of Dover. The Channel is from 20 to 150 miles (32 to 240 km) wide. Narrowest point is the Strait of Dover between Dover, England, and Cape Gris-Nez, France. Ferries cross the strait. Principal islands in the Channel are the Isle of Wight and the seven Channel Islands, all belonging to Great Britain. .) Important ports are Plymouth, Dover, Southampton, Portsmouth, and Folkestone in England; and Cherbourg, Le Havre, Dieppe, and Calais in France. The Channel is rough because currents of the Atlantic and North Sea meet here. Calais and Folkestone are linked by the Channel Tunnel, a 31-mile (50-km) railway tunnel opened in 1994.

For centuries the Channel protected England from invasion by European powers. The last successful cross-Channel invasion of England was made in 1066 by William the Conqueror. The Channel stopped Napoleon in the early 1800's. After the British army retreated across the Channel from Dunkirk in 1940, Hitler began plans for an invasion but he abandoned them after attacking the Soviet Union. The greatest amphibious operation of all times, Operation Overlord, was launched across the Channel by the Allies in 1944.

The first person to swim the Channel was Matthew Webb of England, in 1875. His time was 21 hours, 45 minutes. In 1909 Louis Blériot became the first to fly an airplane across the Channel. In 1926, Gertrude Ederle of the United States became the first woman to make the swim; she crossed in 14 hours, 31 minutes.