South Karelia is a region of forests and lakes. Lake Saimaa is the largest lake in Finland and the fourth largest in Europe. The complete waterways system, of which Lake Saimaa forms a part, consists of a vast group of lakes in eastern Finland. The Lake Saimaa empties its waters, via River Vuoksi, into Lake Ladoga in Russian Karelia. The Saimaa Canal provides an important water link from Lake Saimaa down to the Baltic Sea.
Other large lakes in South Karelia are: Lake Simpelejärvi in the northern part of the region (Parikkala), Lake Kivijärvi in the western part (Luumäki-Lemi) and Lake Kuolimo in the municipalities of Savitaipale and Suomenniemi.
The Salpausselkä ridges were shaped during the final stages of the last Ice Age. The natural environment of the dividers consists of heathland forests which mainly feature pine trees. There are nice hiking trails following the Salpausselkä ridge, for example in Imatra and Lappeenranta. As a contrast to the rugged rocky islands of Saimaa and flat pinewoods, the region features lush deciduous woodlands reaching out from the Ladogian Karelia around Parikkala and Rautjärvi. You can also find wetlands in South Karelia, but not as much as in northern Finland.