The height of the round Mardakan castle is 16 meters. At first it was supposed that this construction consisted of residential part and separately constructed castle column. But during restoration works the territory around the castle had been cleaned it became clear that in the past the castle had a small adjacent area (25 to 25) and high walls. At present, 7 meters high stone wall surrounds the yard. There are towers in the corners of the fence and a hand-rail. The castle built in a form of around column narrows gradually in the upper part. The height has been divided into 3 parts. All these parts are covered with spherical cupola; are connected with stairs in the inside of the wall. In order to let the light in to the 2nd and 3rd floors, there were narrow stripe form windows expanding into inside. A four-cornered tower form castle was built using local white-lime and lime solution. There are three inscriptions with Arabic language writings on it which are located in the top part of the castle door. From the first writing it becomes known that the castle was built at the time of Shirvanshah Hershasi bin Ferrukhzad bin Menichohr (1204-1225). From the second script, we know that the owner of this Round Mardakan castle was powerful İshak bin Kakuli (Hecm Ed and Ad-Din El-Emir İshak b. Kakuli). This person used to be a supreme commander of Shirvan army. In the same writing the construction date of the castle is shown: Hijri calendar, year 600, Morded month (1232-1233 of Christian chronology). At last, the 3rd script shows the name of architect Abd-el-Mecid, the son of Mesud.