Selennyakh Yakut: Силээннээх
Location in the Sakha Republic, Russia
Location
Country	Russia
Physical characteristics
Source
• location	Confluence of the Kharga-Salaa and Nyamnya rivers
• coordinates	69°28′40″N 137°40′34″E / 69.47778°N 137.67611°E / 69.47778; 137.67611
• elevation	420 m (1,380 ft)
Mouth	Indigirka
• coordinates	67°50′41″N 144°54′51″E / 67.84472°N 144.91417°E / 67.84472; 144.91417
• elevation	29 m (95 ft)
Length	796 km (495 mi)
Basin size	30,800 km2 (11,900 sq mi)
Discharge
• average	180 cubic metres per second (6,400 cu ft/s)
Basin features
Progression	Indigirka→ East Siberian Sea

The Selennyakh (Russian: Селеннях; Yakut: Силээннээх, romanized: Sileenneex) is a river in Sakha Republic, Russia. It is a left tributary of the Indigirka.

The length of the river is 796 kilometres (495 mi). The area of its drainage basin is 30,800 square kilometres (11,900 sq mi).^[1]

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.^[2]

According to the State Water Register of Russia, it is a part of the Lena basin district.^[1] The average annual discharge in the mouth is 180 cubic metres per second (6,400 cu ft/s).

• Geography - Yakutia Organized