Fertile Crescent, historic region of the Middle East. A well-watered and fertile area, it arcs across the northern part of the Syrian desert. It is flanked on the west by the Mediterranean and on the east by the Euphrates and Tigris rivers, and includes all or parts of Israel, the West Bank, Jordan, Lebanon, Syria, and Iraq. From antiquity this region was the site of settlements and the scene of bloody raids and invasions.