The Rookery is a medieval earthwork motte and bailey fortress, founded by the Lords of Pevensey. The eastern part of an elongated hillock has been scarped into a motte, with the remaining platform becoming the bailey. Standing against the east bank of the River Cockmere, the castle is encased by wet ditches and with the dense cover of trees, the site is best viewed in winter. Nearby is Burlow Castle and 1 mile east is Wilmington Priory.