Extent
Daoism, without any doubt, is ubiquitous.
Demographical
The exact number of Daoists cannot be calculated. First of all, Daoism can be considered a philosophy, which is not something that can be determined through census as simply as determining one's religion. Also, Daoism does not restrict or bind its followers to only serve and uphold the Daoist principles. It would not be considered a heresy in a Daoist community if one practices, for example, Buddhism simultaneously while practicing Daoism. Daoism's ability to coexist with other religions and beliefs cause many Daoists to not be counted as Daoists in census or survey. Also, many strict Daoists are hermits; they choose secluded places like a cave in order to be in harmony with nature and to emulate what is most natural to a human being Regardless, the number of Daoists who only follow Daoism is estimated to be more than 2.7 million. However, most of the Chinese folk religions, which is believed by mor ethan 390 people, are based on the fundamental ideas of Daoism, which implies that the actual number of Daoists far exceeds what is said in the statistics.
Geographical
Daoism is worldwide. The notions and ideas of Daoism are used by both Daoists and non-Daoists around the world However Daoism, originating from China, is mostly believed in China than any other countries. Despite the the common misconception of Buddhism being the biggest religion in China, Daoism is in fact the biggest religion in China. First of all, the current consensus of what is considered "Daoism" in China is that any folk religion pertaining to Daoism such as Shenism, Animism, and Shamanism, is considered "Daoism" in the survey due to their similar origins. There are currently more than 1500 Daoist temples and 25000 Daoist priests in China. Combined with the number of Dao-related local religions, Daoism easily surpasses the number of Buddhists in China. Another place with concentrated Daoist population is Taiwan. Daoism is the second largest religion in Taiwan, only being beaten by Buddhism, and around 4.5 million people believe in it.