Jianghan Plain is an alluvial plain located in the middle and south of Hubei, China. It shares the border with Dongtinghu Plain. It has an area of more than 30 thousands square kilometers. The region was once a large wetland, but was gradually colonized by settlers beginning in the Neolithic period. This accelerated when the state of Chu established its capital there in the middle of the 1st millennium BC, and when the Qin and Han states built dikes to protect farmland from seasonal floods. The Jianghan area has been an important food grain region of China since at least the Ming Dynasty.