Bryn Bras Castle is a Grade II* listed country house located on the old road between Llanrug and Llanberis known locally as the Clegir road, in Caernarfon, Gwynedd. It was built in a neo-Romanesque style between 1829 and 1835 on the site of an earlier structure by architect Thomas Hopper for Thomas Williams (1795-1874), an attorney at law. The site of the first motorcycle Dragon rally in 1962, the house has been converted into luxury holiday apartments.