The Sunzha (Су́нжа;, ; ) is a river in North Ossetia, Ingushetia and Chechnya, Russia, a tributary of the Terek. It flows northeast inside the great northwest bend of the Terek River and catches most of the rivers that flow north from the mountains before they reach the Terek. It is 278 km long, and has a drainage basin of 12000 km2. The Sunzha rises on the Northern slope of the Caucasus Major. Its major tributaries are the Assa and Argun. With a turbidity of 3800 g/m3, it carries 12.2 million tons of alluvium per year. It is used for irrigation. Cities that lie on the Sunzha include Nazran, Karabulak, Grozny (the capital of Chechnya), and Gudermes. During the First and Second Chechen Wars, the destruction of petroleum reservoirs caused the Sunzha to become polluted with petroleum.

Nomenclature

The origin of the name of the river is disputed. The most probable of versions say Sunzha has come from Mongol-Turkic languages in the deformed type. It is known that Mongols called it Suinchie, Russians Sevenz and in the Chechen language its name got corrective type Solchzha. There is also other version that before Sunzha Chechens called the river Okhi «Oh'-hi, Оhhи» that means «downwards the river».