Chongming, formerly romanized as Chungming, is an alluvial island at the mouth of the Yangtze River in East China covering 1,267 square kilometers (489 sq mi) as of 2010. Together with the islands Changxing and Hengsha, it forms Chongming District, the northernmost area of the provincial-level municipality of Shanghai. At the time of the 2010 Chinese census, its population was 660,000.