Yumen, city in northwestern China, in Gansu Province. It is a transportation and processing center situated in a region with productive petroleum fields. Major rail and highway routes to Xinjiang Uygur Autonomous Region pass through the city, and a pipeline carries crude oil east to refineries in Lanzhou.
Named for the nearby Jade Gate in the Great Wall, Yumen lies on the ancient Silk Road and prospered until modern times as a center of the overland caravan trade. Petroleum production began here in 1939 following discovery of the Laojunmiao oil field and expanded rapidly after vast new petroleum reserves were discovered nearby in 1957. Population (1988 estimate) 91,200.
