Yiyang is a prefecture-level city on the Zi River in Hunan province, China, straddling Lake Dongting and bordering Hubei to the north. According to the 2010 Census, Yiyang has a population of 4,313,084 inhabitants residing in an area of 12,144 km2 (4,689 sq mi). The previous census was in 2000 when it was recorded there were 4,309,143 inhabitants.

Hunan is an inland province of China. Located in the middle reaches of the Yangtze watershed, it borders the province-level divisions of Hubei to the north, Jiangxi to the east, Guangdong and Guangxi to the south, Guizhou to the west, and Chongqing to the northwest. Its capital and largest city is Changsha, which abuts the Xiang River. Hengyang, Zhuzhou, and Yueyang are among its most populous urban cities. With a population of just over 66 million as of 2020 residing in an area of approximately 210,000 km2 (81,000 sq mi), it is China's 7th most populous province, the fourth most populous among landlocked provinces, the second most populous in South Central China after Guangdong and the most populous province in Central China. It is the largest province in South-Central China, the fourth largest among landlocked provinces, and the 10th most extensive province by area.