Aberfan is situated toward the bottom of the western valley slope of the Taff Valley, on the eastern slope of Mynydd Merthyr hill, approximately south of Merthyr Tydfil. When the Merthyr Vale Colliery was sunk on 23 August 1869 by John Nixon and partners, Aberfan consisted of two cottages and an inn frequented by local farmers and bargemen. By 1966 its population had grown to approximately 5,000, most of whom were employed in the coal industry. Since the nationalisation of the British coal industry in 1947, Aberfan's colliery had been under the control of the National Coal Board (NCB). Regulation in the coal industry was provided by HM Inspectorate of Mines. The inspectors had worked as engineers in the coal industry and were former employees of the NCB. The River Taff runs north-to-south through the village; at the upper side of the settlement, on the western outskirts, the bed of the disused Glamorganshire Canal, and a railway embankment run parallel to the river.