The population of Abercynon was recorded as 6,428 in the 2001 Census, decreasing to 6,390 at the 2011 Census, despite more than a hundred additional households built over this period (from 2,582 in 2011 to 2,694 by 2011). The electoral ward of Abercynon includes both the community of Abercynon, but also takes into account the nearby villages of Pontcynon, Ynysboeth and Tyntetown further north.
Abercynon is approximately sixteen miles north of Cardiff and approximately forty miles from Swansea. The rivers Taff and Cynon converge at Watersmeet near Martin's Terrace. Abercynon used to have many churches, chapels and pubs. There are now only four public houses left - The Thorn Hotel, The Navigation, Brownies Bar and the Carne Park Hotel. The only churches still left are St. Donat's Church in Wales, its daughter church, St. Gwynno's, St. Thomas' Roman Catholic Church and the Methodist church in Martin's Lane.
There is a Church in Wales church of St Gwynno and a Roman Catholic church of St Thomas.
Abercynon had a number of nonconformist chapels which were established in the nineteenth century. Most had closed by 2000, including Bethania (Independent), Calfaria (Baptist) and Tabernacle (Calvinistic Methodist).
The village was the terminus of the world's first steam railway journey when on 21 February 1804 the inventor Richard Trevithick drove a steam locomotive hauling both iron and passengers travelled from the Penydarren ironworks in Merthyr Tydfil to the basin of the Glamorganshire Canal at Abercynon. There are memorials to Trevithick's journey at Penydarren and outside the fire station at Abercynon.
The village developed as a transport interchange being at the junction of the Merthyr and Aberdare branches of the Glamorganshire Canal and the Merthyr and Aberdare branches of the Taff Vale Railway. For a time it was known as "Navigation" and the Navigation Hotel, which was originally the headquarters of the Glamorganshire Canal, still bears this name.
Unusually for a village, until early 2008, it had two railway stations. One was on the line from Cardiff to Aberdare, namely Abercynon North. The other, Abercynon South, was on the Cardiff to Merthyr Tydfil line. Following major work, the North station was closed and its services moved to the South station, now named simply Abercynon. Trains are operated by Arriva Trains Wales as part of the Merthyr Line service.