Deir-e Gachin Caravansarai is one of the largest Caravanserai in Iran, located along the historical road of Ray to Qom at the center of the Desert National Park. The unique features of this work have made it “the mother of Iranian caravansaries”. Deir-e Gachin Caravansarai is located in the central part of Qom city, 80 km northeast of Qom (60 km Garmsar highway) and 35 km southwest of Varamin.

This building is called Deir-e Gachin due to a gypsum dome. But now there is no such dome in the building. The caravanserai construction dates back to the Sassanid era and was restored during the Seljuk, Safavid, and Qajar dynasties. Its current form belongs to the Safavid era. This caravanserai was located in the ancient way of Rey to Isfahan. The caravanserai is a square with 109 × 108 meters and about 12,000 square meters in size.

The spaces available can be divided into human, animal and welfare spaces. The building has four rounded towers in the corners. There are also 44 residential rooms, 4 large stables, a mosque, a private yard (independent section and aristocratic section), forage storage, a mill, a bathroom, and 6 toilets. The mosque is probably built at the Sassanid fire temple, where no decorations can be seen.

There are a number of buildings around the Deir-e Gachin Caravanserai, Like two “āb anbār” (Ab meaning water and Anbar meaning storage facility), behind the western side and close to the bathroom, a brick chimney, a water closet, and an Islamic-era cemetery on the southwest side, covered with bricks on its graves.

In the 500 meters of the east of the inn, there is a Mud and Brick building, from the Qajar era, which is in the form of a castle and only has an entrance gate. Deir-e Gachin has a dry desert climate that is characterized by extreme heat and high temperature difference between day and night. The annual rainfall is 40 to 50 mm.