Lying right beside Walna Scar Road, (the ancient packhorse road from Coniston to the Duddon Valley) Boo Tarn is something of a disappointment. Shown on the OS map as being very small, it is heavily silted and overgrown with reeds to the extent that it appears to be a patch of marshy ground beside a stream.

Matters weren't helped by the fact that on the day I visited the sun doesn't even clear the small hillock to the east so the "tarn" lay fully in shadow.