Tianjin was the sea in ancient times, and the land in Han dynasty, but only by the sea.

The seaside in Tianjin is full of mud, and there is no beach. So it is not suitable for fishing by the sea. So there were basically no people at that time.

During the Three Kingdoms period, Tianjin was still a seaside, so there was no name because there was no one.

The ownership of Tianjin in the Three Kingdoms period: bounded by Haihe River, the north of Haihe River belongs to Yuyang County (now the border area between Hebei and Tianjin), and the south of Haihe River belongs to Zhangwu County (now Jinghai County of Tianjin).