Brithdir is a small village in the northern part of the Rhymney Valley near New Tredegar, in the county borough of Caerphilly, south Wales.

It was formed in the early twentieth century to provide housing for men working at the local coal mines including Elliot's colliery.

Centuries before Brithdir was constructed a stone was erected on the mountain top above the village to mark the burial place of Tegernacus, son of Martius.

The stone, believed to have been placed in the 7th century, was originally in a field north west of Capel Brithdir.

This article relating to a location in Caerphilly County Borough is a stub.