Jiangsu has a coastline of over 1,000 kilometers (620 mi) along the Yellow Sea, and the Yangtze River passes through the southern part of the province.

Since the Sui and Tang dynasties, Jiangsu has been a national economic and commercial center, partly due to the construction of the Grand Canal.

Cities such as Nanjing, Suzhou, Wuxi, Changzhou, and Shanghai (separated from Jiangsu in 1927) are all major Chinese economic hubs.

During the Three Kingdoms period, southern Jiangsu became the base of the Eastern Wu (222 to 280), whose capital, Jianye (later renamed to Jiankang), is modern Nanjing.

When nomadic invasions overran northern China in the 4th century, the imperial court of the Jin dynasty moved to Jiankang.

Jiankang remained as the capital for four successive Southern dynasties and became the largest commercial and cultural center in China.

The Ming dynasty, which was established in 1368 after driving out the Mongols who had occupied China, initially put its capital in Nanjing.

Regions surrounding Nanjing, corresponding to Jiangsu and Anhui today, were designated as the Nanzhili province (literally "southern directly governed").

Jiangnan also figures strongly in the Taiping Rebellion (1851 – 1864), a massive and deadly rebellion that attempted to set up a Christian theocracy in China; it started far to the south, in Guangdong province, swept through much of South China, and by 1853, had established Nanjing as its capital, renamed as Tianjing (天京 "Heavenly Capital").

Jiangsu changed hands several times, but in April 1927, Chiang Kai-shek established a government at Nanjing; he was soon able to bring most of China under his control.

This was however interrupted by the second Sino-Japanese War, which began full-scale in 1937; on December 13, 1937, Nanjing fell, and the combined atrocities of the occupying Japanese for the next three months would come to be known as the Rape of Nanjing, after which it became the seat of the collaborationist government of East China under Wang Jingwei, and most of Jiangsu remained under Japanese occupation until the end of the war in 1945.

The decisive Huaihai Campaign was fought in northern Jiangsu; it resulted in Kuomintang defeat, and the communists were soon able to cross the Yangtze River and take Nanjing.

[18] Mount Huaguo, near the city of Lianyungang, is the highest point in Jiangsu, at an altitude of 625 meters (2,051 ft) above sea level.

The old path of the Huai River is now marked by a series of irrigation channels, the most significant of which is the North Jiangsu Main Irrigation Canal (traditional Chinese: 蘇北灌溉總渠; simplified Chinese: 苏北灌溉总渠), which channels a small amount of the water of the Huai River alongside south of its old path into the sea.

Due to its flat terrain, low altitude, and dense population, Jiangsu is one of the most vulnerable regions in China to climate change and its ensuing sea level rise.

[20] Specifically, a ranking on climate change risk of global regions released in early 2023 by The Cross Dependency Initiative (XDI) puts Jiangsu as the most vulnerable of the entire world.

[21] In response to climate disturbance across the country, the fourteenth five-year plan, endorsed by the National People's Congress in 2021, indicates the general direction and various steps towards a low-carbon transition.

The province also plans to recover the damaged coastal regions such as Lianyugang and Yancheng, and improve resilience against rising sea level by implementing seawalls and river floodgates.

[33] In 2022, Jiangsu's GDP adjusted by purchasing power parity was $3.04 trillion, making it the 3rd-largest of any country subdivision globally, behind California and Guangdong.

[35][33] Cities like Nanjing, Suzhou, and Wuxi have GDPs per capita around twice the provincial average, making south Jiangsu one of the most prosperous regions in China.

The province has an extensive irrigation system supporting its agriculture, which is based primarily on rice and wheat, followed by maize and sorghum.

Main cash crops include cotton, soybeans, peanuts, rapeseed, sesame, ambary hemp, and tea.

Other products include peppermint, spearmint, bamboo, medicinal herbs, apples, pears, peaches, loquats, ginkgo.

Silkworms form an important part of Jiangsu's agriculture, with the Lake Tai region to the south a major base of silk production in China.

[39] The economic reforms of Deng Xiaoping have greatly benefited southern cities, especially Suzhou and Wuxi, which outstrip the provincial capital, Nanjing, in total output.

[51] The reports didn't give figures for other types of religion; 80.69% of the population may be either irreligious or involved in worship of nature deities, Buddhism, Confucianism, Taoism, folk religious sects, and small minorities of Muslims.

According to dialects and the other factors, the province can be roughly segmented four major cultural subdivisions: Wu (吴), Jinling (金陵), Huaiyang (淮扬) and Xuhuai (徐淮), from southeast to northwest.

Suzhou is also well known for its silk, Chinese embroidery, jasmine tea, stone bridges, pagodas, and classical gardens.

Suzhou is renowned for its classical gardens (designated as a UNESCO World Heritage Site), as well as the Hanshan Temple, and Huqiu Tower.

Nearby is the water-town of Zhouzhuang, an international tourist destination with Venice-like waterways, bridges and dwellings, which have been preserved over centuries.