The Rhondda and Swansea Bay Railway was a Welsh railway company formed to connect the upper end of the Rhondda Fawr with Swansea, with the chief objective of transporting coal and other minerals to Swansea docks. It was incorporated in 1882, but at first the connection to Swansea from Briton Ferry was refused.

Rhondda, or the Rhondda Valley, is a former coalmining area in South Wales, historically in the county of Glamorgan. It takes its name from the River Rhondda, and embraces two valleys – the larger Rhondda Fawr valley and the smaller Rhondda Fach valley – so that the singular "Rhondda Valley" and the plural are both commonly used. The area forms part of the South Wales Valleys. From 1897 until 1996 there was a local government district of Rhondda. The former district at its abolition comprised sixteen communities. Since 1996 these sixteen communities of the Rhondda have been part of Rhondda Cynon Taf County Borough. The area of the former district is still used as the Rhondda Senedd constituency and Westminster constituency, having an estimated population in 2020 of 69,506. It is most noted for its historical coalmining industry, which peaked between 1840 and 1925. The valleys produced a strong Nonconformist movement manifest in the Baptist chapels that moulded Rhondda values in the 19th and early 20th centuries. It is also known for its male voice choirs and in sport and politics.