AbstractYunnan has the largest number of ethnic groups in China, and its rich set of multiethnic toponyms (place names) has earned itself a nickname of "museum of toponyms". The objectives of this study are to (1) construct a Geographic Information Systems (GIS) database of toponyms in Yunnan from a comprehensive toponymical dictionary series of China, and identify their ethnic roots; (2) enhance the mapping of their spatial patterns and detect possible clusters of ethnic toponyms by spatial analysis methods; (3) analyze the association of multiethnic toponyms with geographic factors by statistical methods; and (4) examine the historical evolution of toponyms. The results show that the highest concentrations of Zang–Mian (Tibeto–Burman) toponyms are in the northwestern and the northeastern mountainous areas, and Zhuang–Dong (Kam–Tai) toponyms cluster in the southwest and the southeast lowlands. In comparison to Han (Chinese majority) toponyms, the Zhuang–Dong toponyms also tend to be closer to rivers and in more remote areas (i.e., farther from major transportation routes and major cities). The centrographic method helps reveal the historical trend of gradual expansion of Han settlement in Yunnan as recorded in the time stamp of toponyms. The paper demonstrates the value of GIS-based analytical methods in toponymical studies.Keywords: historical GISspatial analysismultiethnic toponymYunnanChina AcknowledgmentsThe work reported in this paper spun out of an earlier project supported by the US National Science Foundation (BCS-0623108). Fahui Wang's fieldwork in China was in part supported by the National Natural Science Foundation of China (No. 40928001) and a visiting professorship at Yunnan University of Finance and Economics in the summer of 2012.