Nantong is a prefecture-level city in southeastern Jiangsu province, China. It sits on the northern bank of the Yangtze River, near the river mouth, and is a vital river port. The city borders Yancheng to the north, Taizhou to the west, and the East China Sea to the east; across the Yangtze to the south lie Suzhou, Wuxi and Shanghai.
At the 2020 census Nantong had a population of 7,726,635, of whom 3,766,534 lived in the built-up area formed by its three urban districts.