Haixi Mongol and Tibetan Autonomous Prefecture, locally also known as Qaidam Prefecture (mong. Qaidam; tib. Caindam; chin. Chaidamu), is an autonomous prefecture occupying much of the northern tier of as well as part of the southwest Qinghai province, China. It has an area of 325,785 square kilometres (125,786 sq mi) and its seat is Delingha. The name of the prefecture literally means "west of (Qinghai) Lake."