Lake Urmia is an endorheic salt lake in Iran. The lake is located in the Armenian Highlands, between the provinces of Azerbaijan in Iran, and west of the southern portion of the Caspian Sea. At its greatest extent, it was the largest lake in the Middle East. It is the sixth-largest saltwater lake on Earth, with a surface area of approximately 6,000 km (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).
By late 2017, the lake had shrunk to 10% of its former size (and 1/60 of water volume in 1998) due to persistent general drought in Iran, but also the damming of the local rivers that flow into it, and the pumping of groundwater from the surrounding area. This dry spell was broken in 2019 and the lake began filling up once again, due to both increased rain and water diversion from the Zab River under the Urmia Lake Research Programme. The trend reversed again in early 2020s, and a combination of drought and administrative mismanagement caused a renewed acute drop in water levels. Based on NASA's satellite imagery, the lake has almost entirely dried up by September 2025.