Marysin [maˈrɨɕin] (German: Marienthal) is a village in the administrative district of Gmina Żagań, within Żagań County, Lubusz Voivodeship, in western Poland.
Before 1945 the area was part of Germany. After World War II the region was placed under Polish administration by the Potsdam Agreement under territorial changes demanded by the Soviet Union. Most Germans fled or were expelled and replaced with Poles expelled from the Polish areas annexed by the Soviet Union.
Coordinates: 51°38′14″N 15°20′45″E / 51.63722°N 15.34583°E