The landscape is dotted with 118 permanent glacial lakes, conventionally divided into 17 groups, such as Popovo Lakes, Kremenski Lakes, Banderishki Lakes, Vasilashki Lakes, Valyavishki Lakes, Chairski Lakes, Vlahini Lakes or Tipitski Lakes. The largest of them is Popovo Lake with 123,600 m2, which makes it Bulgaria's fourth largest glacial lake. With a depth of 29.5 m, it is also Pirin's deepest lake and Bulgaria's second. Situated at an altitude of 2710 m the Upper Polezhan Lake is the highest one in the mountain and in the country.