The fortress – castle, citadel is located within the complex of the medieval town of Jajce, at an altitude of 470 meters.
The fortress is an irregular square, which is caused by the configuration of the land. Its volume is 260 meters, and the surface of 4,800 square meters. It is assumed that the fortress existed in the 13th century. Some architectural remains found inside the fortress or within the medieval walls of the city, indicate that here, in mid-15th-century palace was built. The fortress was built over several centuries, repaired and renovated. In the northeast and the southeast corner of the fort are two strong four-sided tower, and it is assumed that one was a tower on the northeast corner. The original entrance to the fortress (barely one meter wide) is located on the west side. In the southwestern part of the fortress is a portal with the royal coat of arms.
King Stjepan Tomasevic, who definitely moved court to Jajce (1421-1461). For the design of the portal with the royal coat of arms in the spirit of the late Gothic, is very similar to the portal with the fortress Bobovac. During the Ottoman period were built support, to strengthen the walls of the fortress. Within the walls of the fortress was a mosque and a powder magazine.
In the era of the Austro-Hungarian rule, in addition to the powder-built water tank.