Ravenscraig is a small castle, built on a narrow rocky promontory in the Firth of Forth. It is naturally defended on three sides by steep cliffs dropping to the sea, and the main part of the castle forms the northern, landward, defence. This comprises two D-plan towers, with outer walls 4.25 metres (13.9 ft) thick, designed to withstand cannon fire. Battlements between the towers formed an artillery platform, with gun holes pointing to landward. The whole is defended by a deep, rock-cut ditch, and is accessed via a bridge
