Sanmenxia (simplified Chinese: 三门峡; traditional Chinese: 三門峽; pinyin: Sānménxiá; Postal map spelling: Sanmenhsia) is a prefecture-level city in western Henan province, People's Republic of China. The westernmost prefecture-level city in Henan, Sanmenxia borders Luoyang to the east, Nanyang to the southeast, the province of Shaanxi to the west and the province of Shanxi to the north. The city lies on the south side of the Yellow River at the point where the river cuts through the Loess Plateau on its way to the North China Plain.