Lake Issyk, Mountain lake in Issyk gorge, Kazakhstan

Lake Issyk lies in the Issyk gorge of the Trans-Ili Alatau, about 40 km east of Almaty. The lake is roughly 1,850 m long, 500 m wide and 50–79 m deep, at an altitude of about 1,714 m. Its water is greenish-blue, and it sits behind a natural dam about 300 m high.

The lake formed 8,000–10,000 years ago when an earthquake-triggered landslide dammed the Issyk gorge with a barrier about 300 metres high. On 7 July 1963 a mudflow from the Issyk River destroyed that dam, emptied the lake and killed around a thousand people in the town of Esik. The dam was rebuilt by the early 1990s, and by the early 21st century the lake had refilled to about three-quarters of its former volume.

The name comes from the Kazakh word "Yesik", meaning door or narrow gorge, later reshaped under the influence of Issyk-Kul. Semyonov-Tien-Shansky recorded the lake's Kazakh name "Jasyl-Kol" (Green Lake) in his diaries. The Caspian tiger lived in the gorge and around the lake into the early 1900s.

The best time to visit is during warmer months when mountain paths are accessible and weather remains more stable. Visitors should expect uneven trails and high elevation, making good gear and acclimatization important considerations.

The Caspian tiger was recorded in the Issyk gorge and around the lake at least into the early 1900s; Pyotr Semyonov-Tyan-Shansky mentions it in his diaries. The geographer also described the water as a thick bluish-green, comparing its colour to Transbaikal beryl, and noted that his guide called the mountain above it Issyk-bash.