Chatham is a town within the Medway unitary authority in the ceremonial county of Kent, England. The town forms a conurbation with neighbouring towns Gillingham, Rochester, Strood and Rainham. In 2020 it had a population of 80,596. The town developed around Chatham Dockyard and several army barracks, together with 19th-century forts which provided a defensive shield for the dockyard. The Corps of Royal Engineers is still based in Chatham at Brompton Barracks.