The spring of Pena starts in the region of Čabriolica and Borisloica, high on the Šar Mountains, 2,500 metres above sea level.

[1] Going through the center of Tetovo it hangs up[clarification needed] in the Polog valley and near the village of Saraḱino it flows into the Vardar.

The most important of these include the Karanikolovska River, the Przhina, the Vejčka, the Lesnhička, and the Brodečka.

From economic view the river is important because on her are built four hydrocenters, one of which was the first in Macedonia.

The Pena family of Caguas, Puerto Rico is rumored to derive its name from the river.