It starts between the southwestern area of the mountainy place called Rila and of the northwestern Rhodope Mountains in Bulgaria. Then it goes through the Pirin mountains and it gets a lot of water from other smaller rivers. It crosses the valley of Nevrokopi and continues between Orvilos and Rhodope, entering Greece through Drama Prefecture. After that it goes to Xanthi Prefecture and cosses a narow and long valley. Eventually at the end, it goes through Xanthi and Chrysoupoli and it drains in the Aegean Sea, making a big delta. 