[1] The river takes its source at an altitude of 403 m in the Chirpan Heights, at 2.7 km northwest of the village of Vinarovo.

It flows in southeastern direction through the Upper Thracian Plain in a wide shallow valley.

The Martinka flows into the Maritsa at an altitude of 87 m at 2.4 km southeast of the village of Brod.

[1] Its drainage basin covers a territory of 395 km2 or 0.75% of the Maritsa's total and borders the drainage basins of the Stara reka and Merichlerska reka to the southwest, the Sazliyka to the northeast, and the Arpadere to the east, all of them left tributaries of the Maritsa.

There are ten villages along its course: Vinarovo, Malko Tranovo, Dimitrievo, Samuilovo, Byal Izvor in Stara Zagora Province, and Stransko, Radievo, Golyamo Asenovo, Brod and Zlatopole in Haskovo Province.