Bassenthwaite Lake is one of the largest lakes in the North West England Lake District in County Cumbria. It is the most northerly lake in the area and the only one bearing the designation ‘Lake’ in its name. The other lakes have names ending in ‘mere’ (meaning more, as in Windermere), ‘water’ (as in Derwent Water) or ‘tarn’.
Bassenthwaite Lake, like most lakes in the area, is elongated and relatively narrow and shallow. The length is more than 6 kilometers, the maximum width is approximately 1.2 km and the maximum depth is 21 meters. The total area covers 5.1 km².
The lake and its surroundings have a wide variety of flora and fauna. Many bird species nest here and the lake contains fish such as salmon, trout, pike, perch, pos and eel. The endangered fish species Vendace (Coregonus vandesius} is said to live there.
The lake is located at a distance of about 3 miles from the town of Keswick and therefore near Derwent Water, which would have once formed a whole. The two lakes are connected by the river Derwent.