Coordinates: 50°57′08″N 0°54′26″E / 50.952330°N 0.907290°E / 50.952330; 0.907290

Lydd is a town in Kent, England, lying on the Romney Marsh. It is one of the larger villages on the marsh, and the most southerly village in Kent. Actually located on Denge Marsh, Lydd was one of the first sandy islands to form as the bay evolved into what is now called the Romney Marsh. The name Hlyda, which derives from the Latin word for "shore", was found in a Saxon charter dating from the 8th century.

The parish of Lydd comprises the town of Lydd, Dungeness, Lydd-on-Sea and parts of Greatstone.

Notable buildings in Lydd include a guildhall and a mediaeval courthouse. Chamberlains and churchwardens accounts of the 15th century survive alongside the town charters.

Lydd reached the height of its prosperity during the 13th century, when it was a corporate member of the Cinque Ports, a "limb" of Romney.

As with much of the marsh, the town was a base for smuggling in the 18th and 19th centuries.

Before World War I Lydd became an important artillery practice camp. Experiments with high explosives carried out on the shingle wastes around 1888 led to the invention of the explosive Lyddite. Lydd was at one time a garrison town and the area is still an important training ground for the armed forces, at one time having an extensive narrow gauge railway network.

Lydd Airport (IATA: LYX, ICAO: EGMD) is located 1.2 NM (2.2 km; 1.4 mi) northeast of the town of Lydd and 12 NM (22 km; 14 mi) south of Ashford in the District of Shepway within Kent, England. It is also known as London Ashford Airport, which officially only refers to its operator.

Lydd Airport has a CAA Ordinary Licence (Number P858) that allows flights for the public transport of passengers or for flying instruction as authorised by the licensee (London Ashford Airport Limited).

Lydd Air is based at the airport, offering regular flights to Le Touquet in northern France.

Lydd Airport was the first airport built in the UK after the Second World War, in 1956. It was used initially for air ferry services, and was known as Lydd Ferryfield. The airlines operating at that time included Silver City Airways (operating Douglas Dakotas) and British United Air Ferries (BUAF) – later becoming British United Airways, (BUA) – which flew Bristol Freighters, Superfreighters and Aviation Traders Carvair aircraft, the latter three types being used for transporting cars and their occupants across the English Channel. One common destination was Le Touquet.