Derwentwater (or Derwent Water) is one of the principal bodies of water in the Lake District National Park in north west England. It lies wholly within the Borough of Allerdale, in the county of Cumbria.
The lake occupies part of Borrowdale and lies immediately south of the town of Keswick. It is both fed and drained by the River Derwent. It measures approximately 3 miles (4.8 km) long by 1 mile (1.6 km) wide and is some 72 feet (22 m) deep. There are several islands within the lake, one of which is inhabited. Derwent Island House, an 18th-century residence, is a tenanted National Trust property open to the public on five days each year.
Derwentwater is a place of considerable scenic value. It is surrounded by hills (known locally as fells), and many of the slopes facing Derwentwater are extensively wooded. A regular passenger launch operates on the lake, taking passengers between various landing stages. There are seven lakeside marinas, the most popular stops being: Keswick, Portinscale and the Lodore Falls, from which boats may be hired. Recreational walking is a major tourist activity in the area and an extensive network of footpaths exists within the hills and woods surrounding the lake.
Open Water Swimming
It is one part of the Frog Graham Round.