A yamen was an administrative office or residence utilized by local bureaucrats and mandarins throughout imperial China, Korea, and Vietnam. While it specifically referred to individual residences or offices of officials, the term also encompassed any governmental body headed by a mandarin at any level of government. This included high-level entities such as the offices of one of the Six Ministries as well as regional prefectural magistracies.
The term has been in wide use within China for centuries. Although it is an ancient concept, it first appeared in English during the Qing dynasty to describe these various governmental structures and residences.