Chatham (/ˈtʃætəm/ CHAT-əm) 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 barracks for the British Army and the Royal Navy, together with 19th-century forts which provided a defensive shield for Chatham Dockyard. The Corps of Royal Engineers is still based in Chatham at Brompton Barracks.