Southerndown is a village in the Vale of Glamorgan, in south Wales. It is southwest of Bridgend, and within the St Brides Major community, close to Llantwit Major and Ogmore-by-Sea. It is mostly known for its beach which backs Dunraven Bay, which is a popular tourist destination during the summer months and since 1972 has been part of a Heritage Coast and is part of the Southerndown Coast SSSI. When the tide is out there is an expanse of sand and pools. The cliffs are an obvious example of sedimentary rock.

The Vale of Glamorgan, locally referred to as The Vale, is a county borough in the south-east of Wales. It borders Bridgend County Borough to the west, Cardiff to the east, Rhondda Cynon Taf to the north, and the Bristol Channel to the south. With an economy based largely on agriculture and chemicals, it is the southernmost unitary authority in Wales. Attractions include Barry Island Pleasure Park, the Barry Tourist Railway, Medieval wall paintings in St Cadoc's Church, Llancarfan, Porthkerry Park, St Donat's Castle, Cosmeston Lakes Country Park and Cosmeston Medieval Village. The largest town is Barry. Other towns include Penarth, Llantwit Major, and Cowbridge. There are many villages in the county borough.