Zhangjiagang , formerly Shazhou County (沙洲县), is a county-level city under the administration of Suzhou, Jiangsu province, China. With 1,246,762 inhabitants at the 2010 census, the city is now part of Jiangyn-Zhangjiagang-Jingjiang metropolitan area with 3,526,260 inhabitants. Continued growth will encompass the Shanghai-Suzhou-Wuxi-Changzhou Metroplex. It borders the prefecture-level cities of Taizhou and Nantong across the Yangtze River, as well as Wuxi to the west.