Cefn viaduct is the third largest in Wales and is a Grade II* listed building. It was designed by Alexander Sutherland in conjunction with Henry Conybeare and partly built by Thomas Savin and John Ward. In early 1866, the project faced disaster when Savin and Ward suffered serious financial and legal difficulties. It was eventually completed with the assistance of Alexander Sutherland. He produced an alternative route into Merthyr, curving the viaduct, so that the railway line avoided property owned by ironmaster Robert Thompson Crawshay. It cost £25,000 to build. It consists of 15 arches, each one 39 feet 6 inches wide, and is 770 ft. long with a maximum height of 115 ft. It was planned to be constructed entirely of limestone like the nearby Pontsarn Viaduct but a trade union strike by stonemasons in February 1866 caused the company to buy 800,000 bricks and use bricklayers to complete the 15 arches. It was completed on 29 October 1866, three years after the main line which linked it with Brecon. The last trains travelled over the viaduct in the mid 1960s and it subsequently fell into disrepair. It was refurbished by Merthyr Tydfil County Borough Council with assistance from a grant from the National Lottery. It has now become part of the Taff Trail, route 8 of the National Cycleway.
Jewish cemetery
Beyond the last buildings of Cefn, parallel to the A470 Merthyr to Brecon road, lies another site of historical interest. This is the Jewish cemetery, one of the largest in Wales outside Cardiff. It was established and consecrated in the 1860s by the then thriving Merthyr Hebrew Congregation. The growth of the Jewish population in the area was mainly linked to the expansion of the mining and ironworks industry in the locality. Many were refugees from Russia, Poland and Romania, fleeing religious persecution. The cost of the land for the cemetery was mainly paid for by the local community, but contributions were also made by Jewish communities and individuals across Britain, the largest amount being £10 from the politician and philanthropist, Baron Lionel de Rothschild. Initially the cemetery was simply a burial ground, with no building on the site. In the late 1890s a simple brick built prayer house was constructed, again using funds raised by the local Jewish community. In 1935, the cemetery was extended, with the new section being formally consecrated in October 1935. A map of the cemetery is held in the archives at Merthyr Tydfil Central Library. The map shows the location of approximately 570 graves, and gives the names and dates of death of many of the deceased. Towards the end of the twentieth century, the Jewish population declined. The community has now left the Merthyr area and responsibility for maintenance of the cemetery has been transferred to the Local Authority.
