It is a partially dilapidated castle located within the Kaf village and next to Kaf Palace. It has walls about five meters high and it is built of black basalt stones and situated atop a mountain to the north of Kaf village. It is surrounded by a wall featuring top of the mountain as a whole. It has four control towers in each of its corners, and a number of rooms used for surveillance In addition to water tanks. The castle can be reached via a winding road of about 1200 m length from the base of the mountain to the castle gate, and it is fit for vehicles. Its establishment dates back to the Nabatean period and it was used during the Islamic period until the beginning of Saudi governance for protecting the passing pilgrims.