The Arg of Karim Khan or Karim Khan Prison was the residence of Karim Khan and where he ruled. It was built in 1180 AH (1766-7) as part of a complex during the Zand dynasty and is named after Karim Khan, and served as his living quarters. It is the biggest and the most important building of the Zand Dynasty. The citadel is located North-East of Shiraz. Its shape resembles a medieval fortress. Karim Khan invited the best architects and artists of the time and bought the best materials from other cities and abroad for the construction of the citadel and had it constructed quickly. The design of the citadel combines military and residential architectures for it was the residence of Karim Khan and had to have high security. Hence, the exterior walls, which essentially resemble the walls of a military castle, are quite tall.

Thus the utter walls, which resemble the walls of a military castle, are very high with a height of about 15 meters. The citadel consists of four high walls. The lower section of the exterior walls is three meters in width. It is shaped like an incomplete cone and its width at the top reaches 2.8 meters. In the upper section of the wall, there is a small chamber, which houses soldiers and guards. Ramparts are built around the top of a castle with regular gap, some of which are small and diagonal for firing arrows or guns. The bigger gaps were for repelling the enemy. The palace’s entrance hall is rather large. Located in the eastern side of the citadel, it has one door which opens to the horse stable and another door, which opens toward the roof. Above  the entrance gate there is a beautiful painting depicting a scene from the battle between Rostam and the White Demon, two mythical personas in the renowned Iranian poet Ferdowsi’s masterpiece ’Shahnameh’. Colorful enameled tiles are used in the painting.  The king’s private bathroom, hall and guards’ residence are constructed behind this wall. There is a balcony in front of which there are two wooden columns and a square pond. The walls of the citadel are made of stone and baked clay is used in other parts of the building. Interior decorations include marbles of Yazd and Tabriz and large mirrors bought from Europe, Ottoman Turkey and Russia. Herbal colors and gold plates are used in the ceilings’ ornaments. The rooms are mainly decorated with flora designs. The citadel has three palaces and its entrance angle is allocated to services section. After the fall of Zand Dynasty and during the Qajar period, the citadel was used as the governor’s seat and turned into the residence of Fars governors. This situation continued until the early years after the coming to power of the Pahlavi dynasty. The tiles of the citadel were repaired at the order of the then governor, Prince Abdulhossein Mirza Farmanfarma (1857-1939). It was converted to the big city prison and was put at the disposal of the police department during the reign of Reza Shah, the first Pahlavi monarch (1925-1941) and afterwards. During all this time, all paintings were covered with plaster and all rooms and halls were turned into small prison cells by constructing walls. The citadel building was put at the disposal of the Cultural Heritage Organization and from this time attention is paid to rehabilitation of the building. Great attention has been paid to rehabilitation of the citadel to preserve the genuineness of the building and its beautiful paintings have been brought to light from under the plaster-work. This is one of the most important monuments of the Zand era and especially that of Karim Khan. It is also important because of depicting the architectural style of this era.