Lake Urmia is a salt lake in northwestern South Azerbaijan near Turkey. The lake is between the provinces of East Azarbaijan and West Azarbaijan, west of the southern portion of the similarly shaped Caspian Sea. It is the largest lake inside Iran and the second largest salt water lake on earth, with a surface area of approximately 5,200 km² (2,000 mile²). At its maximum extent, it is about 140 km (87 miles) long, and 55 km (34 miles) wide. Its deepest point is approximately 16 m (52 ft) deep.