Lydd is a town and electoral ward in Kent, England, lying on Romney Marsh. It is one of the larger settlements on the marsh, and the most southerly town in Kent. 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. Located on Denge Marsh, Lydd was one of the first sandy islands to form as the bay filled in and evolved into what is now called Romney Marsh.