History
In 220 BC, Qin Shi Huang, the first emperor of the Qin Dynasty, established three counties called Yin Mao(鄮) and Gouzhang (句章). Later they were merged into Gouzhang county during the Sui Dynasty. It was renamed Mao county during the Tang Dynasty. It had assumed its current name of "Yin" in the Five Dynasties and Ten Kingdoms period. The city of Ningbo was administrated by Yin county until after the establishment of the People's Republic of China. At the same time, Yin county became a county of Ningbo city. On Apr. 19, 2002, it was renamed Yinzhou District. It is one of the few counties that has kept the same name since its establishment more than 2000 years ago.