County, is the only county in the provincial-level municipality of Shanghai in China. The county consists of three low-lying inhabited alluvial islands at the mouth of the Yangtze north of the Shanghai peninsula: Chongming, Changxing, and Hengsha. Following its massive expansion in the 20th century, Chongming is now the 2nd-largest island administered by the People's Republic of China and the 3rd-largest in Greater China, after Taiwan and Hainan. The county does not, however, administer all of the Chongming: owing to its continual expansion from sediment deposited by the Yangtze, it has merged with formerly separate islands and now includes Jiangsu province's pene-exclave townships of Haiyong and Qilong. The county proper covers an area of and had a population of at the time of the 2010 Chinese census.