Qinghai Lake lies about west of Xining in a hollow of the Tibetan Plateau at above sea level. It lies between Haibei and Hainan Tibetan Autonomous Prefectures in northeastern Qinghai Province in northwestern China. The lake has fluctuated in size, shrinking over much of the 20th century but increasing since 2004. It had a surface area of , an average depth of , and a maximum depth of in 2008.