Shur in the Old Testament
Shur was located outside the eastern border of Egypt. Meaning "a wall." The strip of desert which skirts the wall-like range of jebel er Rahah (E. of Suez, the continuation of the range jebel et Tih northward toward the Mediterranean, still called by the Arabs jebel es Sur) as far S. as wady Gharandel.
Hagar fleeing from Abraham, then in southern Palestine, reached a fountain "in the way to Shur" (Gen. 16:7). She was probably making for her country Egypt by the inland caravan route, the way by Star over jebel er Rahah as distinguished from the coast road by el Arish.
Abraham settled for a time between the two deserts of Kadesh and Shur, and finally sojourned at Gerar (Gen. 20:1). In Gen. 25:18 Shur is defined to be "before (i.e. E. of) Egypt." So 1 Sam. 15:7; 27:8; Josephus (Ant. 6:7) makes it Pelusium, near the Nile's mouth; others the N.E. part of the wilderness of Paran, now al Jifar.
Gesenius makes Shur the modern Suez. Israel entered "the wilderness of Shur" when they had crossed the Red Sea (Exo. 15:22,23). The wilderness of Shur is the whole district between the N.E. frontier of Egypt and Palestine, Shur being derived from the Egyptian Khar (occurring in a papyrus of the 19th dynasty), Kh and Sh being interchanged. In Num. 33:8 the special designation occurs, "the wilderness of Etham" (at the northern extremity of the Bitter Lakes).
International Standard Bible Encyclopedia, which is in the public domain (with minor edits).