seaside resort town and unitary authority, geographic county of Dorset, historic county of Hampshire, England, on the English Channel. The town dates from the erection of a summer residence there by a Dorset squire, Lewis Tregonwell, after 1810. In 1841 there were still only 26 buildings, but thereafter Bournemouth grew rapidly, especially after the coming of the railway (1870). A piped water supply made possible large-scale residential development of the well-drained but agriculturally inferior pine woods and sandy heaths that front the cliff coast east of Poole Harbour. The heaths are dissected by small, steep-sided river valleys, or chines. One of these small streams, the Bourne, now enters the sea through ornamental gardens on the site of the first pier (1860). The main shopping and entertainment centre, with assembly halls and theatres, has grown near the river mouth.

The pleasant climate of southern England, with notably mild winters, not only lengthens the summer tourist season and attracts winter visitors but also favours Bournemouth as a town of retired people. The beaches extend from Alum Chine to Hengistbury Head, and extensive residential areas with distinct local shopping centres lie behind the seafront. Inland sites of light industries have added to the economy of what is still predominantly a resort and residential town. It has also become one of England's main conference and convention centres. Area 18 square miles (46 square km). Pop. (2005 est.) 163,600.