Where is the West Sea and which province does it belong to?

Northeast of Qinghai-Tibet Plateau, Qinghai Province. The West Sea, also known as Qinghai Lake, was formed by the collapse of faults between Datong Mountain, Sun Moon Mountain and Nanshan Mountain in Qilian Mountain. Located in the northeast of the Qinghai-Tibet Plateau, it faces Haiyan, Gangcha, * * and Hainan Tibetan Autonomous Prefecture across the sea in the north, belonging to Qinghai Province.