Lake Tambukan, Protected lake in Stavropol Krai and Kabardino-Balkaria, Russia.

Lake Tambukan is an oval, bitter-salt lake without an outlet, lying on the border of Stavropol Krai's Predgorny district and Kabardino-Balkaria's Zolsky district, 9 km southeast of Pyatigorsk. Its surface covers 1.7 km² at 548 m above sea level, and the water is shallow, between 1.5 and 3.1 m deep. The bed holds a thick black silt.

The water was already known to historical rulers, with military leader Timur visiting in 1395 and a local conflict occurring near its shores in the early 1700s. The area held strategic importance in conflicts between different powers in the Caucasus region.

The name Tambukan derives from Turkic 'Tambu qanı', meaning 'Tambiev's blood' or 'Tambiev's asylum', referring to the 1709 battle in which Kabardian prince Murzarbek Tambiev defeated a Crimean-Turkish army near the lake. A local tradition instead links the name to Murzabek Tambiev's leadership of the Kabardians on the Podkumok River.

The lake lies on the border of Predgorny District, Stavropol Krai, and Zolsky District, Kabardino-Balkaria, 9 km southeast of Pyatigorsk; the settlement of Tambukan is 2 km west and Etoko 1 km south. The whole lake and its surroundings sit in a first-level nature protection zone, so access is restricted. Mud is not taken from the shore but supplied to sanatoria of the Caucasian Mineral Waters.

The lake bed holds about 1.5 million tonnes of black therapeutic mud, used in medicine since 1886; the first chemical analyses were made in 1883 by A. N. Fomin of the Caucasian Mineral Waters administration. The mud is exported beyond the region, and the lake and its surroundings lie in a first-level nature protection zone.