Folkingham Castle was originally a Norman earth and timber ringwork and bailey fortress, founded by Gilbert de Ghent. In 1312, Henry, Baron de Beaumont founded the stone moated castle, when he was granted a licence to crenellate. The large square platform is enclosed by a deep ditch, with a strong counterscarp bank and to the east is an inner barbican and a massive flat bailey, which is outlined by the remnants of its rampart and ditch. In the 19th century, workmen found walls seven-feet thick, when the site was turned into a prison, known as The House of Correction, of which the gate and governor's house survives. 7 miles north-west is Heydour Castle and 19 miles west is Belvoir Castle.