The Demićka rises above the Dunići village at around 1,050 meters above sea level, on the southern slopes of Zāstinje (Backstones, 1,230 m), in Vlašić massif.

The Demićka streams northwest through Dèmići village between the Radohova and Stražbenica mountains.

Below Dunići, the river enters a vertical ravine with a depth of 400 meters.

In spring Vrbanja's tributaries (Ćorkovac, Sadika, Duboka and Ugar's confluence of Kobilja and other streams) flow.

The main tributaries of Demićka are Grozničavica, Djevojački potok and Brestovača.