Tunnsjøen is a lake

Lake

A lake is a body of relatively still fresh or salt water of considerable size, localized in a basin, that is surrounded by land. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds. Lakes can be contrasted with rivers or streams,...

 in the municipalities of Røyrvik

Røyrvik

Røyrvik is a village and municipality in Nord-Trøndelag county, Norway. It is part of the Namdalen region. The administrative centre of the municipality is the village of Røyrvik. The area has always had a strong Sami influence....

 and Lierne

Lierne

Lierne is a municipality in Nord-Trøndelag county, Norway. It is part of the Namdalen region, and it is the largest municipality in Trøndelag. The administrative centre of the municipality is the village of Sandvika. Other villages include Inderdal, Sørli, and Tunnsjø senter...

 in Nord-Trøndelag

Nord-Trøndelag

is a county constituting the northern part of Trøndelag in Norway. As of 2010, the county had 131,555 inhabitants, making it the country's fourth-least populated county. The largest municipalities are Stjørdal, Steinkjer—the county seat, Levanger, Namsos and Verdal, all with between 21,000 and...

 county, Norway

Norway

Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...

. The 100.18 square kilometres (38.7 sq mi) lake lies just south of the large lake Limingen

Limingen

Limingen is a lake in the municipalities of Røyrvik and Lierne in Nord-Trøndelag county, Norway. The lake lies above sea level and has an area of . At the deepest point, it is deep and averages about deep. The lake has a volume of . The lake is located just north of the large lake...

, and just west of the border with 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....

. It is 358 metres (1,174.5 ft) above sea level and has a volume of 8.68 cubic kilometres (2.1 cu mi). The deepest part of the lake is 220 metres (721.8 ft) deep. It is the seventh largest lake in Norway.

Gudfjelløya

The island Gudfjelløya lies in Tunnsjøen lake. It has a high point of 812 metres (2,664 ft) above sea level, which is 454 metres (1,489.5 ft) higher than the lake. This makes Gudfjelløya the highest island on a lake in Norway.