DUMBARTON, royal, municipal and police burgh, seaport, and county town, Dumbartonshire, Scotland, on the river Leven, near its confluence with the Clyde, 151 m. W. by N. of Glasgow by the L.N.E.R. and L.M.S.R. Pop. (1931) 21,546. The Alcluith ("hill of the Clyde") of the Britons, and Dumbreatan ("fort of the Britons") of the Celts, it was the capital of the district of Strathclyde. Here the Romans had a naval station called Theo dosia. The history of the town, however, practically centres in that of the successive fortresses on the Rock of Dumbarton, a twin peaked hill, 240 ft. high and a mile in circumference at the base. The Picts seized it in 736, the Northmen in 87o, and Thomas Crawford of Jordanhill on March 31, 1571, in the interests of James VI. The castle has been held by Queen Mary's adherents, and gave them free communication with France. William Wallace was in 1305 imprisoned in the castle before he was removed to London. The higher of the two peaks is known as Wallace's seat, a tower being named after him. On the portcullis gateway are rudely carved heads of Wallace and his betrayer. Queen Mary, when a child, resided in the castle for a short time. The rock is basalt, with a tendency to columnar formation.
Dumbarton was of old the capital of the earldom of Lennox, but was given up by Earl Maldwyn to Alexander II., by whom it was made a royal burgh in 1221 and declared to be free from all imposts and burgh taxes. Later sovereigns gave it other priv ileges, and all were finally confirmed by a charter of James VI. It had the right to levy customs and dues on all vessels on the Clyde between Loch Long and the Kelvin. "Offers dues" on foreign ships entering the Clyde were also exacted. In 1700 these rights were transferred to Glasgow by contract, but were after wards vested in a special trust created by acts of parliament.
Most of the town lies on the left bank of the Leven, but there is communication with the suburb of Bridgend on the right bank by a five-arched stone bridge. Dumbarton is controlled by provost and council. It unites with Clydebank in returning one member to parliament. The principal industry is shipbuilding. The old staple trade of the making of crown glass, begun in 1777, lapsed some 7o years afterwards when the glass duty was abolished. There are several great engineering works, besides iron foundries, breweries, and rope-yards. There are quays, docks and a harbour at the mouth of the Leven, and a pier for river steamers runs out from the Castle rock, but is now disused. The first steam navigation company was established in Dumbarton in 1815, when the "Duke of Wellington" (built in the town) plied between Dumbarton and Glasgow. But it was not till 1844, consequent on the use of iron for vessels, that shipbuilding became the leading industry.