Dover’s name originated with its river - the River Dour, deriving from the Brythonic Dubrās ("the waters"), via its Latinized form of Dubris. The Romans called it ’’Porte Dubris’’; the modern name was in use at least by the time Shakespeare wrote 'King Lear' (between 1603 and 1606), in which the town and its cliffs play a prominent role.

The town gives its name both to the surrounding chalk cliffs, which a form a gateway to the port; and to the narrow sea passage - the Strait of Dover - on which it stands. The cliffs also gave Britain its ancient name of Albion ("white").

One measure of the importance of Dover's links with France is that only a few English towns/cities have names in French different from their English names: these are Dover (Douvres), London (Londres) and Canterbury (Cantorbéry).

Dover’s history, because of its proximity to France, has always been of great strategic importance to Britain. Archaeological finds have shown that there were Stone Age people in the area; and that by the Bronze Age the maritime influence was already strong. Some Iron Age finds exist also, but the coming of the Romans made Dover part of their communications network. Like Lemanis (Lympne) and Rutupiae (Richborough) Dover was connected by road to Canterbury and Watling Street; and it became Portus Dubris, a fortified port. Forts were built above the port; lighthouses were constructed to guide ships; and one of the best-preserved Roman villas in Britain is here.

Dover figured largely in the Domesday Book as an important borough. It also served as a bastion against various attackers: notably the French during the Napoleonic Wars; and against Germany during World War II.