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 2nd-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 km² (545 sq mi) and had a population of 637,921 at the time of the Census 2020.^[1]

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.

Present-day Chongming first developed as two separate shoals—Xisha and Dongsha—during the Wude Era (AD 618–626) of the Tang dynasty. By the first year of Shenlong (705), a town was established on Xisha which was known as "Chongming".^[2] The number, size, and shapes of the islands fluctuated repeatedly over time and with the floods of the Yangtze River.^[3] In the 15th year of Jiading (1222) under the Southern Song, the islands were part of Tongzhou Prefecture.^[2] These early settlers were mostly fishermen and salt collectors,^[4] with its principal saltern at Tianci. In the 14th year of Zhiyuan (1277) under Kublai Khan of the Yuan, Chongming Prefecture was organized within Yangzhou.^[2] Owing to the shifting sands of the islands, however, the district seat needed to be repeatedly moved.^[3]

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 was exported for use in Songjiang, Hangzhou, and other more developed areas of Jiangnan.^[4] In the 2nd year of Hongwu (1396) under the Ming, the prefecture was elevated to a county^[2] but, shortly afterwards, a major subsidence provoked a mass emigration back to the mainland.^[4] This county was later placed in Suzhou and then Taicang Prefectures.^[2] The unification of over 30 shoals in 1681 was effectively the creation of the present-day Chongming, although it remained much smaller at the time.^[3]

Under the Republic, the county was organized first under the Nantong and then the Songjiang Special Administration District. Nine years after the establishment of the People's Republic of China, it was placed under the municipality of Shanghai in December 1958.^[2] Reclamation, particularly large-scale work on the island's northern and eastern tidal flats in the 1960s and '90s, doubled the size of Chongming between 1950 and 2010.^[3] Dongtan was a proposed ecocity which was planned to open along with the 2010 World Expo in Shanghai but stalled following the 2006 ouster of Shanghai mayor Chen Liangyu.^[5][6]

In mid-2016 Chongming was approved by the State Council of China to upgrade into a district of Shanghai; the District government was formally established in January 2017.

Dongping National Forest Park is located in the district, as are the Dongtan Nature Reserve, the Chongxi Wetland Park,^[3] and the Chongming National Geological Park.^[2] With its unspoiled environment, Chongming Island is one-of-a-kind destination great for eco-tours and restorative vacations. Chongming runs two 4A-class attractions and four 3A-class attractions. The tourism of the island focuses on three zones^[7] – East Chongming, Central Chongming and West Chongming. East Chongming features Dongtan Wetland Park and agritainment options in Yingdong Village and Nanjiang Village. Central Chongming features Dongping National Forest Park, agritainment options at Qianwei Village, Gaojia Zhuangyuan and Ruihua Orchard, Genbao Football Base, Chongming Xuegong (Chongming Museum), Jinaoshan Park, Shou’an Temple and Sanmin Cultural Village. West Chongming offers Mingzhu Lake Park, Xiling Resort, Xisha Wetland and agritainment at Lugang Village.

The district government seat and largest settlement of Chongming is the town of Chengqiao on Chongming Island. There are 227 communities and villages in the district,^[2] administered as 16 towns and 2 townships.

Changxing Island is administered as a single town, also named Changxing. Other town-level divisions of Chongming include (from northwest to southeast): Xinhai, Lühua, Sanxing, Miao, Dongping, Gangxi, Jianshe, Xinhe, Shuxin, Gangyan, Bu, Xianghua, Zhongxing, Chenjia.^[8]

Hengsha Island is administered as a single township, also named Hengsha and Xincun. The other township-level division of Chongming are Qianwei Farm, Dongping Forestry Zone, and Shangshi Contemporary Agricultural Park.

To its southeast along the northern shore is the township of Haiyong; southeast of Haimen is Qilong. Both of these are pene-exclaves of Jiangsu; they are administered from Haimen District and Qidong, respectively.

Shadi dialect is spoken in the district.

Whereas the district was previously only connected to the mainland by ferry service, the Shanghai Yangtze River Tunnel now connects Changxing Island with Pudong in Shanghai, while the Shanghai Yangtze Bridge connects it with Chongming Island. Chongming is presently connected with Jiangsu by the Chongqi Bridge and these three bridges and tunnels form part of the Hushan Expressway connecting northern Shanghai with Xi'an in central China. The Chonghai Bridge connecting western Chongming with Haimen in Jiangsu is under construction.

Hengsha Island is connected via ferry. 18 ferries continue to operate in the district. On Chongming, Chengqiao's Nanmen Port offers service to Shidongkou and Baoyang Rd in Baoshan and to Liuhegang in southern Jiangsu; Xinhai's Niupeng Harbor to Qinglonggang in Haimen;^[12] and other ports offer connections with Wusong and the two other islands of the county.^[2]

The major arteries running along the length of Chongming Island are the Beiyan Highway on the north side and Chenhai Highway on the south. Another 38 highways cross the island. The main artery along the length of Changxing Island is the Panyuan Highway, while Fengle Road runs north and south across central Hengsha Island. There are 41 bus lines in Chongming, connecting over 98% of its 227 communities.^[2]

Chongming line of the Shanghai Metro will link Jinji Road station on Line 9 in Pudong to Chongming via Changxing Island. The first phase of the line from Jinji Road to Changxing Island is currently under construction.

The Tour of Chongming Island International Cycling Race has been held on Chongming Island since 2007. It is held annually and includes a stage race and an UCI Women's Road World Cup race for elite women.

• Li Fengbao (1834-1887) – Qing dynasty diplomat
• Gong Qiuxia (1918-2004), actress and singer