Amlaith was the first King of Arthedain. He was the eldest son and rightful heir of the last King of Arnor, Eärendur. He was a direct descendant of Isildur. After Eärendur, the kings ceased taking their names in the High-elven form.

Amlaith ruled Arthedain from TA 861 until TA 946. He was succeeded by his son Beleg of Arthedain.