In the 19th century, Llanwrthwl was in the county of Brecknockshire, and was a parish in the hundred of Buallt.
On the hills are several cairns, especially on the height named Drygarn, or Derwydd Garn, implying "the Druid's rock, or mount," part of which is in the adjoining parish of Llanfihangel Abergwesyn.