Jääsjärvi

Jääsjärvi (Finnish: [ˈjæːsˌjærʋi]; lit. 'ice lake') is a medium-sized lake of Finland. It is located in the Hartola and Joutsa municipalities, in the Central Finland and Päijänne Tavastia regions. The water quality in the lake is excellent.^[1] 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.

Jääsjärvi
Jääsjärvi
Location	Hartola and Joutsa
Coordinates	61°36′N 26°07′E
Type	Lake
Primary outflows	Tainionvirta
Catchment area	Kymijoki
Basin countries	Finland
Max. length	10 km (6.2 mi)
Max. width	15 km (9.3 mi)
Surface area	81.11 km2 (31.32 sq mi)
Average depth	4.58 m (15.0 ft)
Max. depth	28.2 m (93 ft)
Water volume	0.372 km3 (302,000 acre⋅ft)
Shore length1	303.73 km (188.73 mi)
Surface elevation	92.3 m (303 ft)
Frozen	December–April
Islands	Vehkasalo, Hirtesalo, Kotisalo, Ohrasaari, Urrionsaari, Nautsalo
References	[1]
1 Shore length is not a well-defined measure.

There are dozens of islands in the lake. The biggest are Vehkasalo, Hirtesalo, Kotisalo, Ohrasaari, Urrionsaari, and Nautsalo. Vehkasalo, Hirtesalo, and Ohrasaari have roads connecting them to the mainland.

In winter time, the lake typically freezes.