Nan-tasarion
Pronunciation: naan taa saar' ee own
Source: A Tolkien Bestiary (by David Day)
Nan-tasarion was one of many names for a valley where the River Narog flowed into the River Sirion, in which a forest of willow trees grew. The valley was also called Tasarinan or most commonly, Nan-tathren.
Encyclopedia entry originally written by Fëathoron