The Amalekites were descendants of Esau through his wife Adah (Genesis 36:16; Genesis 36:2). One of Esau’s sons, Eliphaz, fathered Amalek through his concubine Timna (Genesis 36:12). They settled in the south of Canaan in the Negeb (Numbers 13:29), and some also in the hill country of Ephraim (Judges 12:15).1
8 Now David and his men went up and made raids against the Geshurites, the Girzites, and the Amalekites, for these were the inhabitants of the land from of old, as far as Shur, to the land of Egypt.