This entry incorporates text from the public domain Easton's Bible Dictionary, originally published in 1897.
The Valley of Salt, valley of saltpits, valley of Saltpits, or vale of saltpits (Hebrew: גי-המלח) is a place where it is said David smote the Syrians (2 Sam. 8:13). This valley (the Arabah) is between Judah and Edom on the south of the Dead Sea. Hence some interpreters would insert the words, "and he smote Edom," after the words, "Syrians" in the above text. It is conjectured that while David was leading his army against the Ammonites and Syrians, the Edomites invaded the south of Judah, and that David sent Joab or Abishai against them, who drove them back and finally subdued Edom. (Comp. title to Ps. 60 (Ps. 59 in the Septuagint).)
Here also Amaziah "slew of Edom ten thousand men" (2 Kings 14:7; comp. 8: 20-22 and 2 Chr. 25:5-11).