Aberdare is a town in the Cynon Valley area of the principal area of Rhondda Cynon Taf, Wales, at the confluence of the Rivers Dare (Dâr) and Cynon. The population at the 2001 census was 31,705 (ranked 13th largest in Wales). At the 2011 census, the population was 15,808--the difference probably due to a change in boundary definitions. Aberdare is southwest of Merthyr Tydfil, northwest of Cardiff and east-northeast of Swansea. During the nineteenth century it became a thriving industrial settlement, which was also notable for the vitality of its cultural life and as an important publishing centre.
The urban district includes what were once the separate villages of Aberaman, Abernant, Cwmaman, Cwmbach, Llwydcoed, Penywaun, and Trecynon (all redirected here).
By the middle of the 15th century, Aberdare contained a water mill in addition to a number of thatched cottages, of which no evidence remains. In the early 19th century the population grew rapidly, owing to the abundance of coal and iron ore,: the population of the whole parish, 1,486 in 1801, increased tenfold during the first half of the 19th century.
Two major industries supported the growth of the community: first iron, then coal. A branch of the Glamorganshire Canal (1811) was used to transport these products; then the railway became the main means of transport to the South Wales coast. From the 1870s onwards, the economy of the town was dominated by the coal mining industry, with only a small tinplate works. There were also several brickworks and breweries. During the latter half of the 19th century, considerable improvements were made to the town, which became a pleasant place to live, despite the nearby collieries.
With the ecclesiastical parishes of St. Fagan (Trecynon) and Aberaman carved out of the ancient parish, Aberdare had 12 Anglican churches and one Roman Catholic church, built in 1866; and at one time there were over 50 Nonconformist chapels (including those in surrounding settlements such as Cwmaman and Llwydcoed). The services in the majority of the chapels were in Welsh. Most of these chapels have now closed, with many converted to other uses.
For more information, see the EN Wikipedia article Aberdare. This is a long article and mentions by name many men who were leaders of the various churches and industries which were important to the town.
The first three maps are provided by A Vision of Britain through Time
These maps were found on Wikimedia Commons
These maps of Glamorgan post-1974 were found on another site and are very useful for sorting out the up-to-date geography of the area