Issyk-Kul – the largest lake in Kyrgyzstan, is a drainage lake, it is included in the 25 largest lakes in the world and on the 7th place in the list of the deepest lakes. It is located in the north-eastern part of the republic, between the ridges of the Northern Tien-Shan: Kungey Ala-Too and Terskey Ala-Too at an altitude of 1609 m above sea level. The lake is inland, with up to 80 relatively small tributaries flowing into it. Of these, the largest are Tyup and Djergalan, which flow from the east. In the western part, the Chu River very close to the lake, which along the channel of Kutemaldy, 6 km in length, sometimes gives him a part of its waters during the spring floods. The water level in Issyk-Kul varies cyclically (it rises or falls); the cycle takes place over several decades. Water brackish (mineralization of water – 5.90 ‰). The water volume is 1738 km³, the water surface area is 6236 km ², the length of the coastline is 688 km, the average depth is 278 m, the greatest depth is almost 2.5 times larger and is equal to 702 m. The length of Issyk-Kul from west to east is 182 km, and from the south to the north – 58 km. Issyk-Kul is the second most transparent lake in the world, after Lake Baikal.