Folkestone, a market town, seaport, and parish of Kent, England, built partly on the level shore and partly on a cliff on the straits of Dover, 7 m. S. W. of Dover, of which it is a sub-port, and 83 m. S. E. of London by the Southeastern railway; pop. in 1871, 12,694. It was anciently a place of importance, and still has traces of Roman defences. In the 18th century it was the seat of extensive fisheries, and drew still greater wealth from various branches of the smuggling trade, on the suppression of which it fell into decay. Since the opening of the railway, however, which connects at this port with a line of steam packets for Boulogne, it has recovered its prosperity. The harbor has been improved, a fine pier has been built, a custom house established, new warehouses and hotels have been erected, and streets opened. It is said that the town formerly contained five churches, four of which were swept away by the sea; there are now two. An old castle, founded by the Saxon kings of Kent and rebuilt by the Normans, has been almost totally destroyed, together with the height on which it was erected, by the encroachment of the sea.

It is much resorted to for sea bathing.