Lake Urmia is an endorheic salt lake in Iran. The lake is located in the Iranian region of Azerbaijan, near the Armenian border and south of the Caspian Sea. At its greatest extent, it was the largest lake in the Middle East. It was once the sixth-largest saltwater lake on Earth, with a surface area of approximately 6,000 km2 (2,300 sq mi), a length of 140 km (87 mi), a width of 70 km (43 mi), and a maximum depth of 20 m (66 ft).