Marah in the Bible Encyclopedia - ISBE
ma'-ra, mar'-a (marah, "bitter"): The first camp of the
Israelites after the passage of the Red Sea (Ex 15:23; Nu 33:8
f). The name is derived from the bitterness of the brackish
water. Moses cast a tree into the waters which were thus made
sweet (Ex 15:23).
See WANDERINGS OF ISRAEL.