In Lithuania, the Forest Trail first leads through the eastern part of the Sūduva Upland. About 90 km long and 20 km wide, the Sūduva Upland formed in the last Ice Age as the further edge of glaciation. The upland is divided into several parts by the valleys of Šešupė, Kirsna and other rivers. The highest terrain point (282.9 m) in Lithuania is located in the western part of the Sūduva Upland, where Vištytis regional park (Vištyčio regioninis parkas) has been founded for the purpose of protecting landscape, nature and cultural values. The upland then extends into Polish territory. In total, it has around 250 lakes.