Grosmont Castle is an 11th century earthwork motte and bailey fortress, founded by William fitz Osborn. In the early 13th century, Hubert de Burgh founded the stone castle, when adding a rectangular hall block, to the low motte. In 1227, he then replaced the timber palisade with a high curtain wall, flanked by three round towers and a two storey rectangular gatehouse. In the 14th century, the towers and gatehouse were extensively remodelled by the earls of Lancaster, with the north block being given its striking octagonal chimney. The outer bailey, can still be traced by the remains of its mutilated rampart and near the castle bridge, are the foundations of a rectangular medieval building. 5 miles south-east is Skenfrith Castle and 6 miles south is White Castle.