[1][2] The river takes its source from the Icy Lake, the highest of the Musala Lakes at an altitude of 2,709 m, north of the summit of Musala (2,925 m), the highest peak in Bulgaria and the Balkan Peninsula.

[1] It flows in a glacial valley along the western slopes of the summit of Deno (2,790 m).

Until the Borovets ski resort the river valley is deep and forested.

There river flows into the Iskar at an altitude of 964 m in the southwestern part the town of Samokov.

[1][2] The main tributaries are the Solenata Voda (right), the Malka Bistritsa (left) and the Lukovitsa (right).