River Glenderamackin
The River Glenderamackin is a mountain river in Cumberland. It rises on Mungrisdale Common (a few yards from where the Blackhazel Beck rises to run in the opposite direction to the River Caldew) and drains much of the eastern and southern sides of Blencathra, the Glenderamackin carving a small, steep dale below the Bannerdale Crags.
The river runs south-east, then abruptly turns north in Bannerdale, a little valley beneath Bowscale Fell, at the edge of the before sharply turning south to run through Mungrisdale village, skirting almost all around the bottom of Souther Fell.
Latterly, the river turns west at Lowside and is soon swelled by the waters of Mosedale Beck. The Glenderamackin continues past Threlkeld, at which point it joins St John's Beck to form the River Greta
Name
The name "Glenderamackin" is from the ancient British language, and is cognate with the Welsh glyndwfr y mochyn, meaning 'the river valley (glyndwfr) of the pig (mochyn)'. Mungrisdale bears a name of the same origin but from Old Norse: it is from 'Mungo' (St Kentigern) and the Norse gris dalr meaning "Pig Dale".[1]
The 'glendera' element is also present in the name of Glenderaterra Beck, which joins the River Greta shortly after its source.