Chongming Island in the context of "Zhoushan Island"

"Mainland China" is a geopolitical term defined as the territory under direct administration of the People's Republic of China (PRC) in the aftermath of the Chinese Civil War. In addition to the geographical mainland, the geopolitical sense of the term includes islands such as Hainan, Chongming, and Zhoushan. It is also important to note that the terms "the Chinese mainland" or "the mainland of China" are preferred by explicitly pro-Beijing bodies, while the more common term in the English-speaking world and in Taiwan, Hong Kong, and Macau is "mainland China".

By convention, territories covered by the term exclude:

Qidong is a county-level city under the administration of the prefecture-level city of Nantong in southeastern Jiangsu province, China. It is located on the north side of the Yangtze River opposite Shanghai and forms a peninsula jutting out into the East China Sea. It has a population of 967,313 in 2020.

The center of the city is named Huilong Township. It also has a well-known fishing port called Lüsi town, named after Lü Dongbin, one of the eight immortals, who is said to have visited the place four times. Qidong's Qilong township was formerly a separate island in the Yangtze called Yonglongsha but now forms a pene-enclave on Chongming Island, most of which belongs to Shanghai.

Qilong is a township of Qidong in eastern Jiangsu province. The land it occupies was formerly Yonglongsha, a separate island in the Yangtze River delta, but reclamation projects and natural deposition of sediment have joined it to Chongming Island, where it now forms a pene-enclave within Shanghai's Chongming County. Its population was 3436 at the time of the 2010 Chinese census. Qilong's name—literally "opening prosperity"—is a compound of contracted forms of its county and its former island.

Yonglongsha, sometimes translated as the Yonglong Shoal or Yonglong Sands, was a former island in the north channel of the Yangtze River to the north of Chongming in eastern China. It was also known as Yongfengsha and Hefengsha. Prior to its absorption by Chongming, it measured about 16 kilometers (9.9 mi) east to west but was very narrow, with an area of about 14 km (5.4 sq mi).

The islands of Shanghai are those under the jurisdiction of the Shanghai municipal government. They comprise three large inhabited islands and a shifting number of smaller, uninhabited ones. Most are alluvial islands in the Yangtze River Delta in China, although a number of islands in Hangzhou Bay off Jinshan District are also administered by Shanghai. The alluvial islands are relatively young and their number varies over time. In 2006, the city's 19 uninhabited islands covered 226.27 square kilometers (87.36 sq mi), with a total coastline length of 309 kilometers (192 mi).

The Yangshan area of the Port of Shanghai is also located on two islands, Greater and Lesser Yangshan in Hangzhou Bay, but these are administered as part of Zhejiang's Shengsi County.

Hengsha (横沙岛, Shanghainese: Waan So Tau) is a low-lying alluvial island at the mouth of the Yangtze River in eastern China. Together with the islands of Chongming and Changxing, it forms Chongming District, the northernmost area of the provincial-level municipality of Shanghai. Its population was 33,400 in 2008.

Chongming District (pronunciation) is the northernmost district of the provincial-level municipality of Shanghai. Chongming 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 Hainan. Chongming does not, however, administer all of the island: 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. Chongming proper covers an area of 1,411 km (545 sq mi) and had a population of 637,921 at the time of the Census 2020.

The county was established in 1396, the second year of the Ming dynasty's Hongwu Emperor. With the completion of the Yangtze and Chongqi Bridges, it is now connected to both the rest of Shanghai and southeastern Jiangsu province along the Hushan Expressway. Further development is now proceeding according to an urban and agricultural master-plan led by Philip Enquist of SOM, although ambitious plans for an ecocity named Dongtan have been shelved since the 2006 ouster of mayor Chen Liangyu and other neighborhoods have swelled with immigration from people relocated from central China following the completion of the Three Gorges Dam.