Chongming (), formerly romanized as Chungming, is an alluvial island at the mouth of the Yangtze River in eastern China covering 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 .
A stretch of the north shore of the island is not part of Chongming District of Shanghai but are instead two pene-exclaves of Jiangsu, formed by the connection of Chongming to the formerly-separate island of Yonglongsha.
Etymology
The island is named for Chongming, an early settlement on the island of Xisha that was named for its placement on relatively high and clear ground.
History
Present-day Chongming first developed as two separate shoals—Xisha and Dongsha—during the Wude Era (AD 618–626) of the Tang dynasty. These were initially about apart and located south of the larger island of Dongbuzhou (t , s , p Dōngbùzhōu), which came to form part of the peninsula of Qidong in Jiangsu. Xisha was also known as Gujunsha. By the first year of Shenlong (705), a town was established on Xisha which was known as "Chongming". The number, size, and shapes of the islands fluctuated repeatedly over time and with the floods of the Yangtze: In the 3rd year of Tiansheng (1025), a new island arose a little to the northwest of Dongsha which became known as Yaoliusha from the surnames of its early settlers. In the first year of Jiangzhong Jingguo (1101), Sansha rose for the third time, stabilizing 50 Chinese miles northwest of Yaoliusha. During the 12th- and 13th-century Yuan dynasty, Yingqiansha, Matuosha, Zhangpusha, and around six other islands also formed. The early settlers of these islands were mostly fishermen and salt collectors, with their principal saltern at Tianci.
In the 14th year of Zhiyuan (1277) under Kublai Khan of the Yuan, was organized within Yangzhou. Owing to the shifting sands of the islands, however, the county seat needed to be repeatedly moved. During the late Yuan and early Ming, the sparsely-inhabited shoals of the area began to fill with migrants from Pudong and other areas of Songjiang Prefecture. These immigrants introduced cotton cultivation, which spread widely prior to China's opening to international trade in the later Qing. There was small-scale textile production in the area, but most of the cotton was exported for use in Songjiang, Hangzhou, and other more developed areas of Jiangnan. In the 2nd year of Hongwu (1396) under the Ming, the prefecture was downgraded to a county but, shortly afterwards, a major subsidence—sinking the entirety of Dongsha and most of Xisha—provoked a mass emigration back to the mainland. Around the same time, however, Sansha expanded towards the north while Yaoliusha simultaneously eroded in the south while building up in the north, "migrating" it towards Sansha.
Chongming County was later placed in Suzhou and then Taicang Prefectures. Over the course of the Ming, numerous shoals arose in succession: Ma'ansha, Chen'ensha, Gaomingsha, Xiaoyinsha, Changsha, Yuanjiasha, Xiangsha, Gaotousha, and around 20 others. Over the two hundred years from the beginning of Jiajing (1522) under the Ming to the end of Kangxi (1722) under the Qing, these shoals frequently flooded or collapsed back into the river. Yaoliusha and Sansha eroded away; Xisha, Chenensha, Fanliansha, and others sank. In the west, Pingyangsha arose, then sank, then finally merged with nearby Yuanjiasha, Wujiasha, Xiangsha, and Nansha. Around the end of the Ming dynasty in 1644, these islands were merged all the way to Gaotousha in the west, forming a single mass 200 Chinese miles east to west by 40 north to south. Their unification with remaining nearby islands by 1681 effectively created present-day Chongming, although it remained much smaller at the time. Between the Shunzhi and Kangxi Eras (1644–1722), Rilongsha, Yongansha, Ping'ansha, Dongsansha, and around 25 others arose without sinking.