Jääsjärvi

Jääsjärvi is a medium-sized lake of Finland. It is located in the Hartola and Joutsa municipalities, in the Central Finland and Päijät-Häme regions. The water quality in the lake is excellent. The river Tainionvirta has its source in Jääsjärvi and flows through several smaller lakes to Päijänne. The water in Jääsjärvi is bright. The lake is part of the Sysmä catchment area and Kymijoki main catchment area.