Chatham, town, Kent, SE England, on the Medway River. Chatham, Rochester, and Gillingham form a contiguous urban area that is now the unitary borough of Medway. Chatham was a major naval station, with well-equipped dockyards, dry docks, and shipbuilding and repairing equipment; these were ultimately closed by 1984. Some facilities have been preserved for historical and tourist interest; others have been redeveloped for residential or business use. The first dockyard was established by Elizabeth I in 1588. The Roman Watling Street ran through Chatham.

Chatham, city (1991 pop. 43,557), S Ont., Canada, E of Detroit, Mich., on the Thames River. It is an industrial center in a rich mixed farming and fruit-raising region. It was a northern terminus for the Underground Railroad prior to the American Civil War.