Early versions of the name include Brunedun and Brundon reflecting an original name of Bruna or Brune, meaning 'brown one'.

The Brendon Hills are largely formed from the Morte Slates, a thick faulted and folded sequence of Devonian age sedimentary rocks.

The fold couplet is itself offset by displacement of the rocks on the NNW-SSE aligned Timberscombe Fault System.

[5] Over the centuries they have been mined for minerals, notably ironstone from which iron is extracted for making steel.

[6] During the 19th century this activity reached a peak with the West Somerset Mineral Railway, including an 800 feet (244 m) incline, being built to take the ore to Watchet from where it was sent to Ebbw Vale for smelting.