The province of West Azarbayjan has the largest lake of Iran in its territory, known as Lake Orumieh. This lake is at an altitude of 1,267 m. from the sea level, with a length of 130-140 km, the width being approximately 15-50 km. and at an average depth of 50-60 m. Its waters are extremely salty (twice the salinity of the oceans), consequently the lake never freezes.
From olden times, local physicians made use of the water (because of its mineral content) and coastal sludge, in treating skin diseases and rheumatoid disorders. The best season for bathing in these waters are from the end of June till the third week of August, when the lake begins getting cold.
Lake Orumieh has numerous islands, both large and small totaling to 102 in number. The most important of these being the following, Kaboodan (Qoyoon Daqi), Ashk, Espeer, and Arezoo.