Cangwu Commandery (蒼梧郡) was a southern commandery on the lower Xi River, roughly centred on modern Wuzhou in Guangxi and adjoining parts of Guangdong. In Han and Three Kingdoms geography it formed part of the far-flung southern provinces that bordered the lands of the southern peoples and the sea routes towards Jiaozhi and beyond.
Under Eastern Wu, Cangwu was both a frontier region and a convenient place of exile. The frank and incorrupt official Yu Fan repeatedly offended Sun Quan by his sharp remonstrances; after several clashes, Sun Quan banished him to Cangwu, where he died. Other troublesome officials were also posted to the region. Cangwu thus appears in the histories both as a geographic marker of Wu’s southern reach and as a symbol of political banishment to the margins of the state.