In ancient times, this area was called "the middle of the world" (天中), since it was the center of government for Yu province and lay at the heart of the Nine Provinces. The Duke of Zhou (周公), the most influential statesman of the early Dynasty Dynasty, visited Runan many times and termed it as the center of the land. During the Han Dynasty, it contributed the most officials to the central government of any commandery, and was ancestral home to the immensely influential Ru'nan Yuan clan. In former times Runan County was at various times called Ancheng County (安城县) and Ruyang County (汝阳县) amongst others. During the Zhou Dynasty (1045-256 BCE), the vassal State of Dao（道国）fell within the borders of the county.
Today Runan County falls under the jurisdiction of the prefecture level city of Zhumadian (驻马店). With a land area of 1306 square kilometres, the county is home to some 770,000 people (2002 figure). The county government is based in the town of Runing (汝宁镇). The county of Runan was far larger in Chinese history, but had to surrender a lot of its territories to the nearby city of Zhumadian and counties in the recent centuries. This means that today's Runan is much smaller than it was. Since Runan was famous in Chinese history, many historical relics still could be found in the county seat and within its county boundary. Notably, the Nanhai Chan Temple is famous in the Buddhist world. The site where the Duke of Zhou visited became a historical site as well.
^Mote, Frederick W. (1999). Imperial China: 900–1800. Harvard University Press. p. 248. ISBN0-674-44515-5.
^Franke, Herbert (1994). "The Chin dynasty". In Twitchett; Herbert Franke; John King Fairbank. The Cambridge History of China: Volume 6, Alien Regimes and Border States, 710–1368. Cambridge University Press. pp. 264–265. ISBN978-0-521-24331-5.