Ennerdale Water is the most westerly lake in the Lake District National Park in Cumbria, England. It is a glacial lake, with a maximum depth of 150 feet (45 metres), and at ½ mile to a mile (700 to 1,500 metres) wide and 2½ miles (3.9 kilometres) long is one of the smallest lakes in the area. To the west of the lake lies the small village of Ennerdale Bridge. It is close to the port of Whitehaven, the town of Cleator Moor and the village of Cleator.
The lake lies in the eponymous valley of Ennerdale, surrounded by some of the highest and best-known fells in Cumbria including: Great Gable (899 m), Green Gable, Brandreth, High Crag, Steeple and Pillar. Ennerdale Water is fed by the River Liza and other streams, and in turn feeds the River Ehen, which runs to the Irish Sea.