Coniston Water is a medium-sized lake in the English Lake District, in north-west England. Some of the features of Coniston Water, and the surrounding countryside, (together with Windermere) inspired the Lake in Swallows and Amazons, Swallowdale, Winter Holiday, Pigeon Post and The Picts and the Martyrs.

Coniston Water has two islands, one of which, Peel Island, was one of several islands that inspired Wild Cat Island, and is the site of the Secret Harbour. To the north-west of the lake is The Old Man of Coniston, which inspired Kanchenjunga.

Towards the northern end of the Eastern shore of the lake is Bank Ground Farm, the inspiration for Holly Howe. Not far from there is Lanehead, the home of W.G. Collingwood and his family (great friends of Arthur Ransome). Lanehead is one of many houses around Coniston and Windermere that have been put forward as possible models for Beckfoot.