Dover, Strait of

Stretch of water separating England from France, and connecting the English Channel with the North Sea. It is about 35 km/22 mi long and 34 km/21 mi wide at its narrowest part (from Dover pier to Cap Griz-Nez); its greatest depth is 55 m/180 ft. It is one of the world's busiest sea lanes. The main ports are Dover and Folkestone (England), and Calais and Boulogne (France). There are regular ferry services between Folkestone and Boulogne-sur-Mer, and Dover and Calais, as well as hydrofoil services between British ports and Ostende (Belgium) and rail ferries to Dunkerque. The ferry traffic continued after the Channel Tunnel began providing regular rail and car-on-rail services in 1994–95.

The strait was the scene of several historic naval actions, including Hubert de Burgh's defeat of an attempted French invasion of England in 1216, and the Spanish Armada's first setback in 1588, as well as the successful evacuation of encircled forces (mainly British) by the Allies from Dunkerque in May–June 1940.

The geological formation of the channel bed points to the fact that at one time England was joined to continental Europe.