This castle is located to the north-east of Varamin and near Ja'far Abad village. This rectangular structure is made of mud and sun baked bricks. The height of walls are 12 m. Around this village there are trenches with 100 m. intervals.

Its an ancient fortress near the city of Varamin in Tehran. Iraj Castle was one of the important fortresses of adobe with a height of 50 feet, an area of 200 hectares and was built in 1200 in the 100 meters during the Sassanian era.

This monument, the largest mud brick fortress of defense is the world leader in the north to the road Varamin communication and 4 to the gateway in order to enable entry into the building is built. The four gates of the main gate located on the north-east of the great treasures of centuries still remain stable.
A ditch was found around the castle along with six ceramic pieces bearing Pahlavi inscriptions, There is not enough evidence to determine whether the monument was used for military purposes.

Today only the walls of the castle remain which are made of mud and adobe and some of the interior designs can still be seen. Around the castle there are many farms. Iraj Castle is in the shape of a rectangle and has three gates on the North, South and East side of it. This castle is so important that its name was mentioned in Avesta. Iraj Castle was recorded as the world heritage list in 2003.
Three Qanats, underground water canals, were also found, which suggest that the area might have been used for farming.