The Lake Bästeträsk is on the island of Gotland

Gotland

Gotland is a county, province, municipality and diocese of Sweden; it is Sweden's largest island and the largest island in the Baltic Sea. At 3,140 square kilometers in area, the region makes up less than one percent of Sweden's total land area...

, which belongs to Sweden

Sweden

Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....

. The lake lies in the north of the island, approximately 12 km east of Fårösund

Fårösund

Fårösund is a locality situated in Gotland Municipality, Gotland County, Sweden with 862 inhabitants in 2005. The village can be reached by car from Visby. The little island of Fårö can be reached by ferry from Fårösund....

.

With an area of 6.3 km² this is the biggest lake on the island, and it is connected to the Baltic Sea

Baltic Sea

The Baltic Sea is a brackish mediterranean sea located in Northern Europe, from 53°N to 66°N latitude and from 20°E to 26°E longitude. It is bounded by the Scandinavian Peninsula, the mainland of Europe, and the Danish islands. It drains into the Kattegat by way of the Øresund, the Great Belt and...

 with a 250 m long outlet.

The lake is known for its large numbers of rainbow trout

Rainbow trout

The rainbow trout is a species of salmonid native to tributaries of the Pacific Ocean in Asia and North America. The steelhead is a sea run rainbow trout usually returning to freshwater to spawn after 2 to 3 years at sea. In other words, rainbow trout and steelhead trout are the same species....

 and sea trout. In winter the lake is sometimes used for ice skating.