Hay Castle is one of numerous castles in the March, but is unusual in that it has been continuously occupied for the last 800 years. It has a residential keep of c.1200 with a 13th/14th century gateway with pointed archway and portcullis slot. The timber gate survives and has two phases with different styles of carpentry. The north leaf (with wicket) was thought to be 14th century but tree-ring dating now shows that it is a 17th century replacement; the possibly original south leaf with cross-bracing failed to date. The keep is a three-storey residential tower, now unroofed, in which the upper floors were annexed to the adjoining Castle House. Sampling of a first-floor timber fireplace beam showed that the keep had been refitted in the 16th century. Castle House, an early Stuart mansion (NPRN 25592), is built against the tower and the castle enclosure has been adapted for its grounds and gardens.