Windermere is the largest natural lake in England. It is a ribbon lake formed in a glacial trough after the retreat of ice at the start of the current interglacial. It has been one of the country’s most popular places for holidays and summer homes since the arrival of the Kendal and Windermere Railway’s branch line in 1847. It is in the county of Cumbria and entirely within the Lake District National Park. Windermere has also been the venue for the Great North Swim since 2008.