[1] The river takes its source at an altitude of 1,512 m at 300 m west of the summit of Shiligarka (1,577 m) in the mountain range of Sredna Gora.

Its source lies a few kilometers southeast of Sredna Gora's highest summit, Golyam Bogdan (1,604 m).

Following the Pyasachnik Reservoir a few kilometers downstream of the village, the river flows through the Upper Thracian Plain, where the sandy riverbed is corrected with protective dikes.

A 10 km stretch of the third class III-606 road Koprivshtitsa–Strelcha–Trud follows its valley between Pyasachnik Reservoir and the village of Golyam Chardak.

[1] About 2 km upstream of Starosel, along the Pyasachnik's left banks is located Chetinyova Mogila — an important Thracian tumulus, hosting an underground temple and a mausoleum.