What is the largest lake in Norway?

There are at least 450,000 fresh water lakes in Norway. Fewer than 400 have an area of more than 5 km. Most were created by glacial erosion. Europe's four deepest lakes are in Norway, namely Hornindalsvatnet (514 m), Salsvatnet (464 m), Tinnsjø (460 m) and Mjøsa (449 m).