The River Thaw is a river in the Vale of Glamorgan, south Wales. At 20 kilometres/12.4 miles, it is the longest river entirely in the Vale of Glamorgan.

Aberthaw is an area containing the villages of East Aberthaw and West Aberthaw, on the coast of South Wales about 5 miles (8 km) west of Barry. It is home to Aberthaw Cement Works, Aberthaw Lime Works, and Aberthaw Power Station, a decommissioned coal power station that was linked to the South Wales Valleys via the Vale of Glamorgan Railway. The area is historically within the parish of Penmark in the Vale of Glamorgan. The two villages of West and East Aberthaw are separated by the River Thaw. The village of East Aberthaw, near Rhoose, has a 13th-century pub. The village Baptist Chapel and Mission Room no longer exist as such and have been converted for other uses.