Windermere (sometimes tautologically called Lake Windermere to distinguish it from the nearby town of Windermere[a]) is a ribbon lake in Cumbria, England, and part of the Lake District.[5] It is the largest lake in England by length, area, and volume, but considerably smaller than the largest Scottish lochs and Northern Irish loughs.

The lake is about 11 miles (18 km) in length and 1 mile (1.6 km) at its widest, has a maximum depth of 64 metres (210 ft), and has an elevation of 39 metres (128 ft) above sea level. Its outflow is the River Leven, which drains into Morecambe Bay. The lake is in the administrative council area of Westmorland and Furness and the historic county of Westmorland, with the lake forming part of the boundary between the historic counties of Westmorland and Lancashire. It has been one of the country’s most popular places for holidays and summer homes since the arrival of the Kendal and Windermere Railway’s branch line in 1847. The Freshwater Biological Association was established on the shore of Windermere in 1929 and much of the early work on lake ecology, freshwater biology and limnology was conducted here.