 Because the mouth of the Yangtze River moved northward during the Ming dynasty, Haimen has dealt with flooding that destroyed parts of the county, including Lüsi (), Yudong (), and Sijia ().In 1672, under the Kangxi Emperor of the Qing dynasty, the seat moved to Jinghai Township ().Starting from 1701, the river's course moved south, creating more than 40 new sandbanks.