Kyrgyzstan, Issyk Kul, Cholpon Ata. Stand of Poplar trees near Issyk Kul Lake. Issyk Kul is Kyrgyzstan 's largest Lake and at about 180 km long by 70 km wide and 668 meters deep at the deepest point, (the average depth is about 300 meters), it is the world's second largest mountain lake and the fifth deepest lake in the world. The lake has been held in high regard by the Kyrgyz, it is known as the 'Pearl of the Tien Shan' and in 2004, the government declared the lake as the 'property of the nation'.