Comprising an area of 7,620 square kilometres (2,940 square miles),[2] it is bound by Lake Tai to the north, the Qiantang River / Hangzhou Bay to the south, and Tianmu Mountain to the west.
It includes all of the prefecture-level city of Jiaxing, most of Huzhou, and the northeastern part of Hangzhou.
The plain has a humid subtropical climate (Köppen Cfa), influenced by the East Asian Monsoon, with cool winters and very hot and humid summers.
The topography is generally low-lying and flat, at around 3 metres (9.8 feet) elevation,[2] though slightly higher to the south and east and lower sloping towards Lake Tai.
[2] From the 1960s to the 2000s, declining aquifer levels from continual groundwater extraction have caused some of the strongest land subsidence in China.