Lake Þórisvatn in winter

Þórisvatn sometimes anglicized to Thorisvatn is the largest lake of Iceland, most of the time, just ahead of lake Þingvallavatn, situated at the south end of Sprengisandur highland road within the highlands of Iceland.

It is a reservoir of a surface about 88 km2 and is next to the river Þjórsá, which comes down from the glacier Hofsjökull. In the south, it is used by power station. It is like other Icelandic lakes, which are mostly glacial lakes or volcanic lakes, it normally has a stark green color.