The first section of the Merthyr, Tredegar and Abergavenny Railway from Abergavenny to Brynmawr was opened on 29 September 1862. The line was leased and operated by the London and North Western Railway which acquired the smaller railway company on 30 June 1866. Brynmawr station, which opened on 1 October 1862, was at the junction of lines to, and. The Ebbw Vale extension opened in 1867, followed by an extension to the west by the Brynmawr and Blaenavon Railway which constructed a line to Blaenavon which opened to goods traffic on 1 November 1869 and to passengers on 1 January 1870. The final extension was southwards to in 1906 when the Brynmawr and Western Valleys Railway provided a connection with the Great Western Railway's Abertillery branch. The new line, which was on a 1 in 47 gradient fall towards Nantyglo, was jointly worked by the Great Western and the L&NWR, with traffic exchanged between the two companies at Nantyglo. The link created the third route from to Brynmawr, it also being possible to travel via Blaenavon or and the Sirhowy Railway. Brynmawr station was located to the south of the main town centre on an east-west embankment. It has been described as "having something of a Wild West air" due to its lofty location on the edge of town and the wooden buildings which could be very draughty given that Brynmawr is nearly above sea level. To the north of the station was St Mary'sRoman Catholic Chapel and School, while to the west was the Holy Trinity Church. Beyond St Mary's was a mineral line known as Bailey's Tramroad built by Crawshay Bailey in which ran from his ironworks at Nantyglo through Brynmawr to join the L&NWR's Abergavenny line. The station, which had its entrance on the southside, had seven platforms were provided which were a mixture of stone-faced and timber construction. Platform 4 was a bay for Nantyglo which opened in 1906 and was perched on the edge of the embankment. In 1955, 22 trains ran each way between Brynmawr and Newport via Nantyglo, with one train each way running between Brynmawr and. The auto-trains for Blaenavon used platform 3. A glass-panelled footbridge linked the platforms. To the south of the station there were extensive sidings and a turntable suitable for coal tanks. The first of Brynmawr's connections to be lost was the service to Pontypool via Blaenavon which was withdrawn on 5 May 1941. Then the line to Ebbw Vale closed on 3 February 1951, passenger services having ceased on 23 May 1949. Next was the Abergavenny to Merthyr line from which passenger services ceased on 4 January 1958. The last passenger service over the line was an SLS railtour on 5 January 1958 hauled by GWR 6959 No. 7912 Little Linford Hall. Final closure came in November 1959 when coal traffic from ceased. Finally, passenger services on the route to Nantyglo were withdrawn on 30 April 1962 with final closure on 4 November 1963. This was the date on which Brynmawr closed completely with the withdrawal of its goods services.
Present and future
The station site was cleared following the cessation of all traffic in November 1963. It is presently the site of a primary school. The Pontypool and Blaenavon Railway have a long-term ambition to reopen the line from to Brynmawr. However, due to redevelopment of the former alignment, any extension would only go as far as the embankment carrying the B4248 road towards Brynmawr. The proposed station would therefore be at roughly opposite the Blaenant Industrial Estate.