The Dzhardzhan (; ) is a river in the Sakha Republic (Yakutia), Russia. It is one of the northern tributaries of the Lena. The river has a length of â from the source of the Siekotendzhaâ and a drainage basin area of .
The river flows north of the Arctic Circle across the desolate territory of Zhigansky District. Dzhardzhan village, the formerly only inhabited place in the area, is located on the banks of the Lena, close to its mouth. There is an automatic weather station and oil storage tanks in the abandoned settlement.
The Dzhardzhan is a right tributary of the Lena. It has its origin on the western flank of the Orulgan Range, part of the Verkhoyansk Range system, being formed at the confluence of the Malyr-Yuryage and Siekotendzha rivers. It flows roughly westwards, cutting across the Dzhardzhan Range in its upper course and descending into a floodplain in its middle course. Towards the end the Dzhardzhan bends sharply southwestwards and southwards, joining the right bank of the Lena from its mouth.
The longest tributaries of the Dzhardzhan are the long Kende, the long Dzhanchan and the long Ulakhan-Tirekhtyach.