Shanwu,[2] south of present-day Youyuxian, was the seat of Yanmen Commandery during the Qin and Western Han.

[3] The post moved to Yinguan southeast of present-day Shuozhou under the Eastern Han and further south to Daixian under the Kingdom of Wei.

[2] Elevations are generally higher in the south of the county, in which flows the Cangtou River (苍头河); Youyu reaches a north-south extent of 67.7 km (42.1 mi) and east-west width of 45.7 km (28.4 mi).

The monthly 24-hour average temperature ranges from −14.3 °C (6.3 °F) in January to 19.9 °C (67.8 °F) in July, and the annual mean is 4.2 °C (39.6 °F).

Due to the high elevation and dry climate, the diurnal temperature variation averages 16 °C (29 °F) annually.