Brithdir is the name of a number of locations in Wales:

Villages Brithdir, Carmarthenshire Brithdir, Ceredigion Brithdir, Conwy Brithdir, Flintshire Brithdir, Gwynedd, noted for St Mark's Church, Brithdir Brithdir Mawr, Pembrokeshire Brithdir, Powys

Districts of towns Brithdir, Caerphilly Brithdir, Bridgend