Abstract:

Since ancient times， Dunhuang has been a chokepoint of communication between Chinese and western civilizations. Emperor Wu of Han Dynasty set up four counties to control the Hexi Region， and Dunhuang Prefecture was located in the west， with six counties under its jurisdiction， which was a strategic place to control the Western Regions. The location of the six counties has long been an important component of Dunhuang's historical research， but the location of some of the city sites is still controversial. This paper presents a comprehensive analysis of the environmental characteristics of several identified city sites， combining documentary and fieldwork analyses. The results show that there is a pattern that the sites are river-based and located at the intersection of mountainous alluvial fan margins and oases. The reason of this pattern is that the alluvial fan margin zone has good conditions for agricultural production， and is generally located near transportation routes， so given the vastness of the land that can be reclaimed， this zone is the most suitable for the agricultural peoples of the Central Plains， who is the first to dominate the Hexi Region， to reclaim. This pattern provides a new perspective for the study of the location of oasis towns in the arid zone， and indicates that the currently debated site of Yuanquan County should be in the location of the ancient city of Hanhunao， rather than the ancient city of Sidaogou as earlier thought by scholars.

Key words: Dunhuang Prefecture, Han Dynasty, city site, historic environment, city site selection, Yuanquan County