Haiyong is a town of Haimen District in Nantong, Jiangsu, China. Together with neighboring Qilong, it forms a pene-enclave of the province on Chongming Island, most of which belongs to the province-level municipality of Shanghai. Haiyong presently covers about 12.5 square kilometers (5 sq mi) and had a population of 5,004 during the year 2000 census.