Sudovian Upland (Lithuanian: Sūduvos aukštuma) is a hilly terrain in the south-west of Lithuania, north-eastern Poland, and eastern Kaliningrad Oblast. It is a part of the Baltic Uplands. The current terrain of the uplands was formed after the last ice age as a result of repeated regressions during warmer periods and progressions during colder periods.
The topography is hilly with rolling terrain. The northern part is dominated by large and medium-sized hills of morainic loam, the southern edge by small gravelly and sandy hills.
There are around 250 lakes in the area. The deepest lake in Poland, Hańcza, is located in the uplands, as well as other deep and large lakes, such as Wigry Lake and Vištytis Lake. The Peršėkė and Šešupė rivers flow through the Sudovian Upland. [1]
Vištytis Regional Park, Meteliai Regional Park and Veisiejai Regional Park are located within the uplands