Chongming county consists of Chongming Island – the third-largest in China after Taiwan and Hainan – and the two small islands of Changxing and Hengsha, situated in the mouth of the Yangtze River. The county is the northernmost part of Shanghai. Its pillar industries are ship-building, agriculture, and tourism.
Previously connected to the mainland only by ferry, massive infrastructure development in the new century has introduced road links via the Yangtze River Tunnel and Bridge and the more recent Chongqi Bridge, critical components of the G40 Shanghai–Xi'an Expressway. The Yangtze River Bridge, which opened in 2009, is a cable-stayed structure almost 10 kilometers in length, with a 730 meter central span. The box girder Chongqi Bridge, opened two years later, connects Chongming with the city of Qidong, in Jiangsu Province, to the north.
Visitors are drawn to Chongming by its abundance of preserved green space. The island is of particular ecological significance due to its importance for migratory bird species. Its Dongping National Forest Park 东平国家森林公园 is Shanghai's largest cultivated forest, and a show-piece for the country's reforestation plans. Cycling and horse-riding trails are provided for visitors. Other major green tourism attractions are provided by the Dongtan Wetland Natural Protection Zone 东滩湿地公园 and Dongtan Bird Reserve 东滩鸟类保护区.