أَصْغَر ; سُفْلَى
Lake Roś (Polish: Jezioro Roś, German: Roschsee) is a lake in the Masurian Lake District of the Warmian-Masurian Voivodeship of Poland. This S-shaped glacial lake has an area of 18.9 km2 and a depth of 31.8 metres. The Swięcek and Konopka rivers flow into the lake, while the Pisa River flows out of it. The largest town on the lake is Pisz.