Nantong (Chinese: 南通; pinyin: Nántōng; former names: Nan-t'ung, Nantung, Tongzhou, or Tungchow; Qihai dialect: [nie tʰoŋ]) is a prefecture-level city in Jiangsu province, People's Republic of China. Located on the northern bank of the Yangtze River, near the river mouth, Nantong is a vital river port bordering Yancheng to the north, Taizhou to the west, Suzhou and Shanghai to the south across the river, and the East China Sea to the east. The population is 7,282,835 at the 2010 census whom 1,994,708 live in the built up area made of 3 urban districts.

The prefecture-level city of Nantong administers 8 county-level divisions, including 3 districts and 3 county-level cities and 2 counties.

These are further divided into 146 township-level divisions.

Because the coast of the East China Sea is constantly moving eastward as the Yangtze River adds silt to its delta, the distance between Nantong and the seashore is getting farther than the one in ancient times. From the time of the Han dynasty through to the Tang dynasty, what is now called Nantong was a minor county subordinate to Yangzhou. By 958 AD a city of sufficient importance had developed for a new, independent prefecture called Tongzhou ("Opening Prefecture", possibly from its position near the mouth of the Yangtse) to be created. The increasing wealth of Yangzhou caused Tongzhou to be once again eclipsed as an administrative centre in 1368. When Tongzhou finally regained prefecture status in 1724, it was renamed Nantong ("Southern Tong") to avoid confusion with another Tongzhou, located near Beijing.