Rivers flowing west from Suomenselkä drain to the Gulf of Bothnia and the lakes in the east drain to the Gulf of Finland. Geographically, the area is relatively flat, with highest altitude variations being 20 m. Because of the low relief, there are bifurcation lakes. Historically, this very sparsely populated region separated Ostrobothnia from the southern and eastern lake regions of Finland.
Rivers originating from Suomenselkä flow westward to the Gulf of Bothnia, while lakes in the east drain to the Gulf of Finland. Geographically, the area is relatively flat with minimal elevation changes, ranging up to 20 meters. Due to low relief, there are bifurcation lakes. Historically, this sparsely populated region has separated Ostrobothnia from southern and eastern lake regions of Finland.