Aberdare, a town and parish of Glamorganshire, S. Wales, at the junction of the river Bare with the Cynon, 20 m. N. N. W. of Cardiff, and 4 m. S. W. of Merthyr Tydvil; pop. of the parish (25 sq. m.) in 1861, 32,299; in 1871, about 40,000. In 1841 the population was but 0,471. The increase is due to the great extension of coal and iron mining. The coal is largely consumed in the iron mills of the town, and a considerable amount is exported. There are many fine public and private buildings, good water works, and a public park.