It drains parts of the Ihtimanska Sredna Gora mountain range and the Sofia Valley.

The river takes its source under the name Lopushna at an altitude of 1,1167 m on the northern foothills of the summit of Golyama Ikuna (1,221 m), the highest point of the Belitsa ridge in Ihtimanska Sredna Gora.

It then enters the Ognyanovo Reservoir, turns westwards and reaches the Sofia Valley at the village of Doganovo.

At the village of Ravno Pole it again turns northwest and flows through the Chelopechene neighbourhood of the capital Sofia.

The Lesnovska reka flows into the Iskar at an altitude of 510 m at 1.6 km northwest of the village of Svetovrachene.