Mangnai Zhen, or Mangnai town (茫崖镇 Mangya Zhen, sometimes written Mangya Chen or Mengzhen), at 38°15' 20"N, 90°18'40"E, 2,945 m, is a very remote oil-refinery town about 10 km southeast of Shimiankuang, in Mangnai County in Qinghai Province, China. It is just across the provincial border of Xinjiang Uyghur Autonomous Region of which it was formerly apart.