The Swansea Valley (Welsh: Cwm Tawe), one of the South Wales Valleys, is the name often given to the valley of the River Tawe area in Southern Wales, UK. It reaches southwest and south from the Brecon Beacons National Park down to the city of Swansea. Today, administration of the area is divided between the City and County of Swansea, Neath Port Talbot County Borough, and Powys. A distinction is often drawn between the Lower Swansea valley and the Upper Swansea valley which have different characters; the former was more heavily industrialised during the 19th and 20th centuries.
Notable towns and villages in the area include Clydach, Pontardawe, Ystradgynlais, Ystalyfera and Abercraf.
In its September 2005 document Towards a Valleys Strategy, Neath Port Talbot County Borough Council notes "a marked divide between the more remote communities at Ystalyfera and along the Twrch and Amman valleys and the reasonably prosperous southern communities of Pontardawe, Alltwen, Rhos, and Trebanos." The area is served by the A4067 Swansea-Brecon road, but has had no rail connection since passenger services on the former Midland Railway line between Swansea and Brynamman via Ystalyfera ceased in 1952.