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, 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. Its current population is 7,282,835 at the 2010 census, 1,994,708 of whom live in the built-up area made up of three urban districts.
In September 26, 2004, the first World Metropolitan Development Forum was held in Nantong. In 2005, Nantong had a GDP growth of 15.4%, the highest growth rate in Jiangsu province, and in 2016 Nantong's GDP had a total of about 675 billion yuan, ranking the 21st in the whole country.
Although the city took a blow from the economic depression of the 1930s, as well as the Japanese occupation of the 1930s and 40s, Nantong has remained an important center for the textile industry. Because of its deep-water harbor and connections to inland navigational canals, it was one of 14 port cities opened to foreign investment in recent Chinese economic reforms.
Nantong was the first place in China to be developed into a modern city after the collapse of the Qing Dynasty, and was also the birthplace of China's modern industry.
The prosperity of Nantong has traditionally depended on salt production on the nearby seacoast, rice and cotton agriculture, and manufacture of cotton textiles, especially Nantong blue calico. A local statesman and industrialist named Zhang Jian founded Nantong's first modern cotton mills in 1899. He then developed an industrial complex that included flour, oil, and silk reeling mills, a distillery, and a machinery shop. He also founded a shipping line and reclaimed saline agricultural land to the east of Nantong for cotton production. Thanks to these efforts, by 1911 Nantong was commonly called "Zhang Jian's Kingdom". In the early Republican period, the Nantong Special Administrative District included Chongming County, now part of Shanghai.
Because the coast of the East China Sea is constantly expanding eastward as the Yangtze River adds silt to its delta, the distance between Nantong and the seashore is getting longer than it once was in ancient times.
Nantong has a humid subtropical climate (Köppen Cfa), with four distinct seasons. Winters are chilly and damp, and cold northwesterly winds caused by the Siberian high can force temperatures to fall below freezing at night although snowfall is relatively uncommon. Summers are hot and humid, and downpours or freak thunderstorms often occur. Monthly daily average temperatures range from 3.1 °C (37.6 °F) in January to 27.2 °C (81.0 °F) in July, and the annual mean is 15.33 °C (59.6 °F). With the plum rains in June and early July comes the rainiest part of the year.