Grisedale Tarn is an attractive tarn, lying in a depression at the heads of three valleys between Seat Sandal, Fairfield and Dollywaggon Pike. The outflow is to the north-east, into Grisedale Beck which flows down to Patterdale.

Just below the outfall is Wordsworth's Brothers Parting stone. It is a memorial to his brother John, this being the place they last saw each other and parted on September 29th 1800. John Wordsworth was the Commander of the East Indiaman "Earl of Abergavenny" when she sank off Portland on 5 Feb 1805. More than 250 died, including John Wordsworth.

The shipwreck was so serious that it resulted in the launch of the first life boat in Weymouth in 1805. The wreck was also one of the earliest salvage attempts with a diving bell, by a Mr Braithwaite who employed the bell and gunpowder to uncover and collect the treasures. John Wordsworth's sword can be seen at Rydal Mount.

In the 1880s, Canon Rawnsley, founder of the National Trust, arranged for William's memorial poem to be inscribed on the rock.

'Here did we stop; and here looked round
While each into himself descends,
For that last thought of parting Friends
That is not to be found.
...
Brother and friend, if verse of mine
Have power to make thy virtues known,
Here let a monumental Stone
Stand--sacred as a Shrine.'

Legend has it that King Dunmail, last king of Cumbria, did battle with Edmund I of England and Malcolm I MacDonald of Scotland in the pass between Grasmere and Thirlmere. Dunmail was killed in the battle and is buried at Dunmail Raise, on the pass. Some of Dunmail's warriors fled with the crown of Cumbria, climbing to Grisedale Tarn where they threw it into the depths for safekeeping until some future time when Dunmail would return. Every year the warriors are said to return to the tarn, recover the crown and carry it down to the cairn on Dunmail Raise. There they strike the cairn with their spears and a voice is heard from deep inside the stones, saying "Not yet, not yet; wait a while my warriors."