White Castle (), Llantilio Crossenny is a medieval castle in Monmouthshire, Wales. The name "White Castle" was first recorded in the thirteenth century, and was derived from the whitewash put on the stone walls. The castle was originally called Llantilio Castle (recorded in the Pipe Rolls in 1186), after Llantilio Crossenny, the medieval manor of which it was a part. Known as one of the “Three Castles”, there has been a defensive structure at the site since the late eleventh century. The castle ruins are Grade I listed as at 19 November 1953.