The English Lake District is made up of series of over 80 glacial lakes, mountain tarns and several reservoirs. Of these around 20 are considered significant.
The sizes of the lakes varies, with Windermere being the largest in both length and width (10 x 1 miles or 17 x 1.6 Km). The deepest of the lakes is Wastwater with a maximum depth of 250 feet (76 metres).
Only Bassenthwaite Lake, is officially referred to as a lake, the remaining names end in either water or mere. - the latter term refers to a lake that is broad in relation to its depth. A tarn is used to refer to any small lake although it originally meant a form of glacial mountain lake.