DERWENTWATER, a lake of Cumberland, England, in the northern part of the celebrated Lake District (q.v. for the physical relations of the lake with the district at large). It is of irregular figure, approaching to an oval, about 3 m. in length and from 12 m. to 114 m. in breadth. The greatest depth is 70 ft. The lake is seen at one view, within an amphitheatre of mountains of varied outline, overlooked by others of greater height. Several of the lesser elevations near the lake are especially famous as view-points, such as Castle Head, Walla Crag, Ladder Brow and Cat Bells. The shores are well wooded, and the lake is studded with several islands, of which Lord’s Island, Derwent Isle and St Herbert’s are the principal. Lord’s Island was the residence of the earls of Derwentwater. St Herbert’s Isle receives its name from having been the abode of a holy man of that name mentioned by Bede as contemporary with St Cuthbert of Farne Island in the 7th century. Derwent Isle, about six acres in extent, contains a handsome residence surrounded by lawns, gardens and timber of large growth. The famous Falls of Lodore, at the upper end of the lake, consist of a series of cascades in the small Watendlath Beck, which rushes over an enormous pile of protruding crags from a height of nearly 200 ft. The “Floating Island” appears at intervals on the upper portion of the lake near the mouth of the beck. This singular phenomenon is supposed to owe its appearance to an accumulation of gas, formed by the decay of vegetable matter, detaching and raising to the surface the matted weeds which cover the floor of the lake at this point. The river Derwent (q.v.) enters the lake from the south and leaves it on the north, draining it through Bassenthwaite lake, to the Irish Sea. To the north-east of the lake lies the town of Keswick.