The Sumbar (also Sari-su, Sara-su and Ṣáríṣú) is a fast flowing river in southern Turkmenistan and northern Iran. It a tributary of the Atrek. The name Sari-su means yellow water in Turkic languages, but is applied to a number of other rivers as well. It used to be an area for Caspian tigers in Turkmenistan, until the last individual was killed in January 1954.
The Sumbar is 245 kilometres (152 mi) long and drains a basin of 8,300 square kilometres (3,200 sq mi). It arises in the Kopet Dag mountains in Iran and flows into Turkmenistan. For a long stretch before the Sumbar runs into the Atrek, it is separated from it by a range of hills called the Marábeh. The Atrek becomes the Turkmenistan-Iran border where the Sumbar flows into it, at .
- Geptner, V. G., Sludskij, A. A. (1972). Mlekopitajuščie Sovetskogo Soiuza. Vysšaia Škola, Moskva. (In Russian; English translation: Heptner, V.G., Sludskii, A. A., Komarov, A., Komorov, N.; Hoffmann, R. S. (1992). Mammals of the Soviet Union. Vol III: Carnivores (Feloidea). Smithsonian Institution and the National Science Foundation, Washington DC).
- Fraser, James Baillie (1838) "Notes on the Country Lying between the Meridians of 55° and 64° East, and Embracing a Section of the Elburz Mountains in Northern Khorásán" Journal of the Royal Geographical Society of London 8: pp. 308-316, p. 310
- This article includes content derived from the article "Сумбар" in the Great Soviet Encyclopedia, 1969–1978.