The third geographical region is the Beqaa Valley. This central highland between the Lebanon Mountains and the Anti-Lebanon Mountains is about in length and 9.6 to 16 kilometers wide and has an average elevation of . Its middle section spreads out more than its two extremities. Geologically, the Beqaa is the medial part of a depression that extends north to the western bend of the Orontes River in Syria and south to Jordan through Arabah to Aqaba, the eastern arm of the Red Sea. The Beqaa is the country's chief agricultural area and served as a granary of Roman Syria. Beqaa is the Arabic plural of buqaah, meaning a place with stagnant water.