Hen Dŷ Cwrdd is the oldest Nonconformist chapel in the Cynon Valley. The ancient St John’s Parish Church (founded 1189) and Hen Dŷ Cwrdd chapel were the only two places of worship to be built in the parish up to 1811. The Hen Dŷ Cwrdd Blue Plaque was unveiled on 22 April 2010 by Cllr Robert Smith and Reverend Dafydd Owen (Welsh Religious Buildings Trust).