Chatham (Ang.-Sax. Cetheham), a parliamentary, and, since 1891, municipal borough, river-port, fortified town, and naval arsenal, in the county of Kent, situated on the right bank of the Medway, at the upper part of its estuary, 30 miles E.S.E. of London. It forms almost one continuous town with Rochester (q.v.) on the west, but itself has few objects of interest, being much of it ill built and irregular, although great improvements have been effected in recent years. The High Street is mile long, parallel to the river. Chatham owes its importance to its naval and military establishments, situated at Brompton, a suburb on high ground overlooking the Medway. There is also a large convict establishment. The Chatham fortified lines are the frequent scenes of sham-fights and reviews. Pop. (1851) 28,424; (1871) 45,792; (1891) 59,389, of whom 31,711 were in the municipal borough. The borough sends one member to parliament. Traces of Roman villas have been found, with Roman bricks, tiles, coins, and weapons. The dockyard was founded by Elizabeth before the threatened invasion of the Spanish Armada. In 1662 it was removed to its present site. In 1667 the Dutch, under De Ruyter, sailed up the Medway, and, in spite of the fire from the castle, destroyed much shipping and stores.
In a military point of view, the lines of detached forts connected with Chatham constitute a fortification of great strength; and the whole is regarded as a flank defence for London in the event of an invader seeking to march on the capital from the south coast. In 1888 an additional chain of forts was being built by convict labour over a wider area. The place is also defended by some strong forts on the Medway. In and near Chatham are Fort Pitt, a military hospital and strong fort; Melville Hospital, for marines and sailors; barracks for infantry, marines, artillery, and engineers; a park of artillery; and magazines, storehouses, and depôts on a large scale.
Chatham is one of the principal royal ship-building establishments in the kingdom, and a visit to it never fails to impress the stranger with a sense of the naval power of England. The dock-yard is nearly two miles in length, containing several building-slips, and wet-docks sufficiently capacious for the largest ships; and the whole is traversed in every direction by tramways for locomotives, with a gauge of 18 inches. Three great wet-docks on reclaimed marsh land were completed in 1883 after the labour of 17 years, and at a total cost of about £3,000,000 (including cost of site; as also convict labour valued at £400,000). The reclaimed land extended to 400 acres; and the aggregate water area of the three new wet-docks is 67 acres. A duplicate of Brunel's block-making machinery is kept at Chatham to supplement that at Portsmouth. In the navy estimates provision is made for about 5000 artisans and labourers. A statue of Lieutenant Waghorn, the pioneer of the 'overland route' to India, was erected near the railway station in 1888; but Chatham's most cherished memories are of Dickens and Gordon: of the latter there is a statue, mounted on a camel, by Onslow Ford (1890). Lord Rosebery opened a new town-hall, English Renaissance in style, 23d January 1900.