Lake Matianus

Lake Urmia
Lake Urmia from space in 1984
Coordinates	37°42′N 45°19′E / 37.700°N 45.317°E / 37.700; 45.317Coordinates: 37°42′N 45°19′E / 37.700°N 45.317°E / 37.700; 45.317
Type	salt (hypersaline) lake
Primary inflows	Zarriné-Rūd, Simineh-Rūd, Mahabad River, Gadar River, Barandouz River, Shahar River, Nazlou River, Zola River, Qatur River, Kaftar Ali Chay, Aji Chay, Boyuk Chay, Rudkhaneh-ye Qal'eh Chay, Qobi Chay, Rudkhaneh-ye Mordaq, Leylan River
Primary outflows	none: all water entering the lake is lost through evaporation
Basin countries	Iran
Max. length	140 km (87 mi)
Max. width	55 km (34 mi)
Surface area	5,200 km2 (2,000 sq mi)
Max. depth	16 m (52 ft)
Salinity	217–235 g L−1 Na–(Mg)–Cl–(SO4) brine 8–11% in spring, 26-28% in late autumn
Islands	102 (see list)

Lake Urmia (Persian: دریاچه ارومیه‎‎, Daryāche-ye Orūmiye; Azerbaijani: اورمیا ﮔﺆﻟﻮ, Urmiya gölü) is an endorheic salt lake in Iran. The lake is between the provinces of East Azerbaijan and West 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 and the sixth-largest saltwater lake on Earth, with a surface area of approximately 5,200 km² (2,000 sq mi), a length of 140 km (87 mi), a width of 55 km (34 mi), and a maximum depth of 16 m (52 ft). The lake has shrunk to 10% of its former size due to damming of the rivers that flow into it, and the pumping of groundwater from the surrounding area.

Lake Urmia, along with its once approximately 102 islands, is protected as a national park by the Iranian Department of Environment.

Currently, the lake is named after the provincial capital city of Urmia, originally an Assyrian name meaning puddle of water. However, in the early 1930s, it was called Lake Rezaiyeh (Persian: دریاچه رضائیه‎‎) after Reza Shah Pahlavi. After the Iranian Revolution in the late 1970s the lake was renamed Urmia.

Its Old Persian name was Chichast, meaning "glittering", a reference to the glittering mineral particles suspended in the water of the lake and found along its shores. In medieval times it came to be known as Lake Kabuda (Kabodan), from the word for "azure" in Persian, or 'կապույտ' (kapuyt) in Armenian. Its Latin name was Lacus Matianus, so it is referred to in some texts as Lake Matianus or Lake Matiene.