Shan (simplified Chinese: 单; traditional Chinese: 單; pinyin: Shàn) is a Chinese surname. The origin of this surname is not clear. One explanation is that it came from Shan County in Shandong province. Another possible origin involves King Cheng of Zhou's youngest son's acquisition of the name when he was given what would become the Shan state when the enfeoffment system was enacted during the Zhou Dynasty. The Shan state existed for a few hundred years before it was annexed by a stronger neighbouring state. It was located in present-day Jiyuan, Henan province. Although the surname comes from the place name, the Shan family was a branch of the royal family of the Zhou Dynasty. Its ancient origin determines its rareness and not many people have the Shan surname. According to one unverifiable estimate, about 150,000 people are of the surname.
Shan could also be used to refer to the rare surname . The rare character was unable to be rendered on a computer so people chose Xian 冼 to replace it. People from Gaozhuang Village born after the system change and people who didn't want a hassle with technology were affected. The choice was controversial as some people saw that future generations would forget their name.
Most of people of the Shan surname live in Shandong, Henan and Hebei. However, some people bearing the Shan surname can be found in Taiwan and overseas Chinese communities throughout the world.
Some ethnic peoples adopted "Shan" as their surname but its pronunciation is mostly "Chan". Some Manchu and Hui people choose "Shan" as their family name, but their population is small. Majority of the Shan are Han Chinese and they can trace their origin to the Zhou Dynasty.