| Selennyakh Yakut: Силээннээх | |
| Source1 Location: | Confluence of the Kharga-Salaa and Nyamnya rivers |
| Source1 Coordinates: | 69.4778°N 137.6761°W |
| Source1 Elevation: | 420m (1,380feet) |
| Mouth: | Indigirka |
| Mouth Coordinates: | 67.8447°N 144.9142°W |
| Mouth Elevation: | 29m (95feet) |
| Subdivision Type1: | Country |
| Subdivision Name1: | Russia |
| Length: | 796km (495miles) |
| Discharge1 Avg: | 180m3/s |
| Basin Size: | 30800km2 |
| Pushpin Map: | Russia Sakha Republic |
| Pushpin Map Caption: | Location in the Sakha Republic, Russia |
The Selennyakh (Russian: Селеннях; Yakut: Силээннээх|translit=Sileenneex) is a river in Sakha Republic, Russia. It is a left tributary of the Indigirka.
The length of the river is 796km (495miles). The area of its drainage basin is 30800km2.
It originates in the north-west of the Chersky Range. The river flows southeastwards through the Moma-Selennyakh Depression which is bound in this area by the Burkat and Khadaranya ranges, and in the east by the Selennyakh Range, then the river flows across the Ust-Yansky District, where Sayylyk, the only inhabited place of its basin is found.
In its middle course the Selennyakh makes a wide bend northeastwards and then flows across the Aby Lowland in a roughly eastern direction until it reaches the left bank of the Indigirka. The Selennyakh is frozen between October and May.[1]
According to the State Water Register of Russia, it is a part of the Lena basin district. The average annual discharge in the mouth is 180m3/s.