Zagros Mountains

West of Zanjan, the Qezel Ozan winds through a region of steep ridges and narrow valleys. Its tributaries descend from the surrounding highlands before the river turns north and east through the mountains. Farther downstream it joins the Shah Rud and continues as the Sefid Rud towards the Caspian Sea. The broken terrain separates the high Iranian plateau from the wetter northern slopes, with river gorges providing passages through otherwise formidable mountains.