A detailed understanding of the mercury footprint at subnational entity levels can facilitate the implementation of the "Minamata Convention on Mercury", especially for China, the largest mercury emitter worldwide. Some provinces of China have more than 100 million people, with economic activities and energy consumption levels comparable to those of smaller G7 countries. We constructed a stochastic, nested multiregion input-output (MRIO) model, which regionalized the China block in the EXIOBASE global-scale MRIO table, to model the mercury footprint associated with global supply chains spanning China's regions and other countries. The results show that Tianjin, Shanghai, and Ningxia had the highest per capita mercury footprint in China, which was comparable to the footprint of Australia and Norway and exceeded the footprint of most other countries. Some developed regions in China (e.g., Guangdong, Jiangsu) had higher mercury final product-based inventories (FBI) and consumption-based inventories (CBI) than production-based inventories (PBI), emphasizing the role of these regions as centers of both consumption and economic control. Uncertainties of Chinese provincial mercury footprint varied from 8% to 34%. Our research also revealed that international and inter-regional final product and intermediate product trades reshape the mercury emissions of Chinese provinces and other countries to a certain extent.