Lusatia is a historical region in Central Europe, territorially split between Germany and modern-day Poland. Lusatia stretches from the Bóbr and Kwisa rivers in the east to the Pulsnitz and Black Elster rivers in the west, and is located within the German states of Saxony and Brandenburg as well as in the Polish voivodeships of Lower Silesia and Lubusz. Major rivers of Lusatia are the Spree and the Lusatian Neisse, which defines the border between Germany and Poland. The Lusatian Mountains of the Western Sudetes separate Lusatia from Bohemia in the south. Lusatia is traditionally divided into Upper Lusatia, the hilly southern part, and Lower Lusatia, the flat northern part.