The Big Lake on Pelister Nationl Park is post glacial lake. Located in the original part of Ezerska River, a left tributary of the river Sapuncica, east of top Vrteska on altitude of 2218 m.
The Big Lake is caused by the interaction of erosion and accumulative glacial processes in the concave part of the cirque, the southern and eastern side is surrounded by moraine embankment, whose length is 320 m.
Toward the direction southwest – northeast, the lake is 223 m long, and its greatest width in the south east – north west is 166 m. The total length of the lake is 785.25 m, and in this context, it covers an area of 42,000 m2.
Maximum depth of 14.5 m, according to which it is the third deepest natural lake, and deepest mountain lake in the Republic of Macedonia. In the basin of the lake accumulate a total of 185,374 m3 of water.
The lake can be reached on foot from several places, the road through Nizo Pole is recommended which is approximately 4 hours walking. In summer Big Pelister lake can be reached with off-road vehicle (4 x 4).
Near Big Lake is located mountain home, which with prior notice is open for tourists and visitors.