Bassenthwaite Lake is a body of water in the Lake District in North West England, near the town of Keswick. It has an area of 5.3 km2 (2.0 sq mi), making the fourth largest of the lakes in the region. The lake has a length of approximately 4 miles (6.4 km) long and maximum width of 0.75 miles (1 km), a maximum depth of 19 m (62 ft), and a surface elevation of 68 m (223 ft) above sea level. Its primary inflow and outflow is the River Derwent, which drains into the Irish Sea at Workington. The lake is in the unitary authority of Cumberland, and the ceremonial county of Cumbria.