Charles Ellicott Commentary 1 Samuel 15:7

"And Saul smote the Amalekites, from Havilah as thou goest to Shur, that is before Egypt." — 1 Samuel 15:7 (ASV)

From Havilah until you come to Shur. —The Havilah here alluded to cannot be now identified. Shur, which signifies “wall,” probably refers to the wall which crossed the northeast frontier of Egypt, extending from Pelusium, past Migdol, to Hevo. Ebers suggests that this wall gave to Egypt the name of “Mizraini,” the enclosed, or fortified.