Hai'an, a county-level city entrusted by Nantong City, Jiangsu Province, is named after the meaning of "sea water never rises". It is located in the south-central part of Jiangsu Province, at the junction of Nantong, Yancheng and Taizhou; It borders the Yellow Sea in the east, Rudong in the southeast, Jiangyan District of Taizhou in the west, Rugao in the south, Taixing in the southwest, and Dongtai in the north; Hai'an has the longest east-west straight line of 71.1 kilometers and the widest south-north straight line of 39.35 kilometers, with a total area of 1184 square kilometers. It has jurisdiction over 4 streets, 9 towns, 1 national development zone, 1 provincial high-tech zone, 1 provincial trade logistics park, and 1 Laoba Port Binhai New Area. The municipal people's government is located at No. 106, Changjiang Middle Road, Zhongcheng Street. According to the data of the seventh population census, as of 0:00 on November 1, 2020, the permanent resident population of Hai'an City was 874334.

Hai'an is the origin of Jianghai civilization. The Qingdun Site in Hai'an traces the history of the Jianghuai Plain back to 6000 years ago. The Qingdun Site represents the advanced level of the eastern Jianghuai Plain in the Neolithic Age. Here, the immortal myth of seven victories in the seven wars between the Soviet Union and Central China and the revolutionary firewood of the Jiaoxie Red Flag People's Corps are left. Hai'an is a comprehensive transportation hub formed in history. The Shangguanyunyan River was dug in the Han Dynasty to pass through Hai'an Town. The Ningqi Railway and Xinchang Railway pass through Hai'an. The Yantong High-speed Railway under construction passes through Hai'an. Hai'an City is "the hometown of poultry and eggs in China", "the hometown of cocoons and silk in China", "the township of lakes and mulberry in China", "the township of puffer fish in China", and "the township of laver in China". In 2018, Hai'an was successfully nominated as the National Civilized City Nominated City. In 2021, Jiangsu Province will build a pilot city of beautiful and livable cities.

In 2020, Hai'an will achieve a regional GDP of 122.1 billion yuan, an increase of 5.8%; Completed 237 billion yuan of industrial taxable sales, ranking first in the north of the Yangtze River in Jiangsu Province; The taxable sales of the service industry was 182 billion yuan, and the construction output value of the construction industry was 180 billion yuan. In 2021, the regional GDP will reach 134.309 billion yuan, up 9.1% year on year.