Historically speaking, there were two major sources of surname Yang: one came from the title of a state and the other the name of a county. Both of these two branches originated from surname Ji and they were the direct descendants of Yellow Emperor, the origin of Chinese nation.
As of the first case, a historic record compiled in Southern Song Dynasty showed that Shang Wen, the youngest son of Emperor Xuan of Zhou Dynasty, was granted with the title of Marquis Yang by Emperor You. But after State Yang was destroyed by State Jin, the people of the conquered state took Yang as their surname ever since.
Another source of surname Yang stemmed from the adoption of the name of a county. Shu Yu, the third son of Emperor Wu of Zhou Dynasty was granted with title and territories in Jin. During the reign of Duke Wu, Emperor Li of Zhou conferred Duke Wu with the territories of Yang, a place in today's Shanxi province. Later Bo Qiao, son of Duke Wu was granted with title of Marquis Yang. Since, people there began to take Yang as their surname.
Starting from Northern Wei Dynasty, many ethnic minorities abandoned their surname and took the surname of Yang, making Yang a multi-ethnic surname.
In early times, people with surname Yang lived in Huayin county, Shaanxi province. Thanks to the population migration, other places around Huayin such as Tongguan, Lingbao and Luoyang became the second source of surname Yang.
After the Yellow Turbans Uprising in late Tang Dynasty, people with surname Yang began to move southward, with their population extending to Hunan, Hubei, Zhejiang, Jiangxi, Guizhou and Fujian.
During Song Dynasty, people with surname Yang mainly settled in Zhangzhou, east China's Fujian province, making the coastal region the center of Yang people.
Yang Xiang, a man in Fujian in Ming Dynasty entered Taiwan in 1420, and later Yang people from Guangdong province also came to settle in Taiwan. During the flourishing age in Qing Dynasty, many Yang people moved to Taiwan province.
By People's Daily Online