Bastam Castle complex is located nine kilometers west of Zia al-Din on a rocky height overlooking the Bastam village and Aq Ҫay River.
According to the historical and archaeological resources, Urartu fortress-city of Bastam was established in the first half of the seventh century BC, under the reign of Rusa II (685-465 BC), the Urartu king, and named RUSAII-URU-TUR which means Rusa small city. The archaeological site is placed on a nearly single mountain at the exit of Aq Ҫay River, in the middle of mountainous valleys at its entering point to Chaypareh plain. It includes three main parts: 1) the bottom of castle (including the southern entrance as the main entrance to castle and its related spaces like security room, armory, warehouse and columned hall; 2) the middle of the castle (including the temple of Khaldi and liquid storage warehouse) and 3) the top of castle including different buildings belonged probably to the ruler of the castle.
Other architectural structures like residential neighborhood, eastern building and northern gate are placed on the hillside, in the eastern and northern sides of the castle. In addition, a long and huge stone wall discovered by Wolfram Kleiss, the German archaeologist, is related to the hydraulic system of the castle.