The Dospat (, Despatis) is a river in the Western Rhodope Mountains, the most important tributary of the Mesta. It takes its source from the 1643-metre-high Rozov vrah ("Rose Peak") in Bulgaria and flows southeast until Dospat Dam, after which it turns southwest to continue generally to the south and flow into the Mesta as a left tributary near the village Mikrokleisoura on Greek territory just south of the Greek-Bulgarian border. The Dospat has a drainage basin of 633.5 km2. Its length is 110 km, of which 79 km is in Bulgaria and 21 km in Greece. For a small distance of 3 km it forms the Greek–Bulgarian border.