Holywell Castle Mound is a Norman earthwork motte and bailey fortress, built on a narrow steeply-sided promontory. Sited on its northern tip at the confluence of two dingles, the motte is set on a bailey platform, which is defended by a broad ditch. The timber castle changed hands between the Welsh and the English numerous times, it was burnt by Ranulf III, earl of Chester in 1209, who then rebuilt the castle identified at 'Treffynnawn' in 1210. The fragment of masonry sticking out of the steep eastern slope, could be part of the castle or the remains of demolished cottages. The site which overlooks St Winefride's Well is very overgrown with a dense cover of trees, so is best viewed in winter. 5 miles south-east is Flint Castle and 11 miles west is Rhuddlan Castle.