Salasel Castle is located in the north of Shushtar city on top of a huge rock. According to the evidence, the castle was built in Sassanid period. It had been surrounded by a deep moat from east to west having a common border with the river on the west side. The same characteristic had turned the castle into a resistant military fortress against the enemy’s attacks. The distinctive feature of the castle making it different from other castles is the same passage of Darian River through underneath the castle, access to the water of the river through staircase inside the castle. The feature makes it possible for people inside the castle to resist against the attacks for months and years at time of blockade by the external forces. The structure of castle is divided into different parts: 1. Shoadan; 2. Bathhouse; 3. Kitchen; 4. Bakeries; 5. soldiers' home (Qourkhaneh); 6. several gates (Qapi); 7. Gardens; 8. Naqareh Khaneh. The castle had included a huge Shoadan which was somehow related to other Shoadans inside the city. The Shoadans kept the temperature low, at 25 degrees Celsius, in the warm environment of Khuzestan province with 40 degrees Celsius. The castle used to have two huge gates. The impregnability factors of the castle, in total, include: 1. The location of the castle on a natural rock; 2. The existence of the moat around the castle; 3. The establishment of high towers and walls around the castle; 4. Having strong military facilities and equipment which were used when needed; 5. Access to the water of river made it possible to defend the castle for a long time.
Constructed in oval shape, Salasel Castle is among multi-dimensional type of castles. The towers of castle are circular-shaped. The building has been reconstructed and repaired for several times. A state mansion was erected in the north of the castle by the ruler of Khuzestan in Qajar period.