Windermere (historically Winder Mere) is a ribbon lake in Cumbria, England. It is within the Lake District and is the largest lake in England by length, area, and volume, although considerably smaller than the largest Scottish lochs and Northern Irish loughs.
Windermere 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. For administrative purposes the lake is in the unitary authority area of Westmorland and Furness, and it historically formed part of the boundary between Westmorland and Lancashire.