Kuli kalon Lakes is the second largest lake in the Fann Mountains, and is located in the Ayni region of Tajikistan, the northwestern part of the Gissar Mountains. Kuli Kalon translates as "Big Lake", and the area of the lake is 0.52 km², with a catchment area of 43.9 km². Kuli kalon Lake is in fact, also the name of a group of lakes, each of them also has own name, but among them Kuli Kalon is the largest. This is why the name Kuli Kalon is often wrote in the plural form. Other lakes are located at the western edge of the Kuli kalon basin, with a height of more than 2800 m above sea level.
Kuli kalon has two tributaries from the south and from the east side and the outflow is from the North West side. In the water system, the Kuli kalon Lake is the last link in the water chain.