Markarfljót is one of the many braided glacial rivers to be found on the south coast of Iceland.
The river is approximately 100 kilometers long and the main sources for the river are the glaciers Mýrdalsjökull and Eyjafjallajökull.
It flows through narrow gorges in the mountainous area between the glaciers Tindfjallajökull and Torfajökull, then spreads in the wide sand plains at Iceland’s south coast, near Þórsmörk.
The Markarfljót takes its course first north, then west of Þórsmörk and finally empties into the Atlantic west of Eyjafjallajökull. One of the Markarfljót’s tributaries is the river Krossá, flowing through Þórsmörk, which is notorious for sudden changes in its water level.