Yancheng is a prefecture-level city in Jiangsu province on China's eastern coast. It is the largest city in Jiangsu by jurisdictional area and lies along the Yellow Sea, which forms its eastern boundary. Within the province it borders Lianyungang to the north, Huai'an to the west, Yangzhou and Taizhou to the southwest, and Nantong to the south.
The city was formerly known as Yandu. It existed as a county before being established in its present form as a city on January 18, 1983.