Issyk Kul (also Ysyk Köl, Issyk-Kol: Kyrgyz: Ысык-Көл Russian: Иссык-Куль) is an endorheic lake in the northern Tian Shan mountains in eastern Kyrgyzstan. It is the tenth largest lake in the World by volume and the second largest saline lake after the Caspian Sea. Although it is surrounded by snow-capped peaks, it never freezes; hence its name, which means "hot lake" in the Kyrgyz language (Chinese: 熱海; literally "Hot Sea" in Chinese texts).
The lake is a Ramsar site of globally significant biodiversity (Ramsar Site RDB Code 2KG001) and forms part of the Issyk-Kul Biosphere Reserve. It was the site of an ancient metropolis 2,500 years ago, and archaeological excavations are ongoing. Lake Issyk Kul has a length of 182 kilometres (113 mi), a width of up to 60 kilometres (37 mi), and covers an area of 6,236 square kilometres (2,408 sq mi). This makes it the second largest mountain lake in the world behind Lake Titicaca in South America. Located at an altitude of 1,607 metres (5,272 ft), it reaches 668 metres (2,192 ft) in depth.