The Eagle Mountains
were the range of "black, snow-capped" mountains which stretched across the north of Prydain
, and which contained Caer Dathyl
, Medwyn's Valley
, The Black Lake
, and the Northern Realms
including Fflewddur's Kingdom
The range was bordered to the southwest by the River Kynvael, to the southeast by the River Ystrad, and to the south by the uplands of the Hill Cantrevs.