- Source: Alcock Tarn
Alcock Tarn is a lake in Westmorland and Furness, Cumbria, England. It is located high in the fells on Heron Pike, roughly a mile and a half east of Grasmere.
Alcock Tarn was originally known as Butter Crags Tarn and was enlarged by means of a stone and earth dam in the 19th century to a depth of about 6 ft (1.8 m). The owner, a Mr Alcock of Grasmere, then stocked it with brown trout.