The factual accuracy of this map is disputed.Differs from two sources listed below, original researched synthesis with official Census' population data, at least Inner Mongolia is inaccurate (en:Talk:Religion in Inner Mongolia#Minzu University Survey)Religion with an absolute majority (50%+) of believers by province of China. Map based on this other map (1) and this other one (2), and also on the most recent demographic analyses available.

Legend:   Chinese traditional religions and local religions   Buddhism   Islam   Cult of the Heaven, cult of aobaoes, and Mongolian shamanism
Own work of Aethelwolf Emsworth based on this map (1) (original source: DUMORTIER, Brigitte, 2002, Atlas des religions, Autrement, collection Atlas, Paris, p. 32.), this map (2) (original sources: Narody Vostochnoi Asii ("Ethnic Groups of East Asia" (1965)), Zhongguo Minsu Dili ("Folklore Geography of China" (1999)), Zhongguo Dili ("Geography of China" (2002)), and on the most recent demographic analyses available.
Aethelwolf Emsworth.