Hengnan County derives its name from its location south of Mount Heng (Nanyue), the sacred southern peak of China. It spans longitude 112°6′E to 113^o;8′E and latitude 26^o; 32′N to 26^o;58′N. It is located in the southeast of Hengyang City, Hunan Province, it borders Anren County in Chenzhou to the east, Leiyang City and Changning City to the south, Qidong County and Hengyang County to the west, Hengyang, Hengdong, and Hengshan County to the north. The county encircles the urban area of Hengyang City from three directions - east, south, and west. 

The County People's Government is located on Huangjin Road in Yunji Town, 27.5 kilometers away from the Hengyang Municipal Government. The administrative region is a U-shaped hilly basin, with its terrain categorized into plains, terraces, hills, and mountainous areas. The highest peak is Tianguang Mountain (814.9 meters above sea level) on the eastern border, while the lowest point (59 meters above sea level) lies in Huajiang Village, Xiantang Town. Located within a subtropical monsoon climate zone, the entire county experiences warm and humid conditions. Thermal resources remain abundant throughout the year, though rainfall distribution shows significant seasonal concentration. Spring is marked by erratic temperature shifts and unstable weather systems. Drought conditions prevail recurrently during summer and autumn months. Winters exhibit relatively short cold spells, while extended periods of intense heat dominate the summer season. The average annual temperature is 17.8 ℃ , the annual rainfall is about 1268.8 millimeters, and the frost free period is 287 days throughout the year.

Hengnan has a long history. Established as Líng County in 202 BCE during the 5th regnal year of Emperor Gaozu of the Western Han Dynasty, this territory underwent successive administrative transformations over two millennia. These included establishing prefectures (jun), creating sub-prefectures (zhou), partitioning counties to form prefectural seats (fu), and redefining municipal boundaries. In 1756 CE (21st year of the Qianlong reign, Qing Dynasty), the southeastern sector was detached to establish Qingquan County. Finally, through systematic regional reorganization, Hengnan County was formally instituted in July 1952, culminating a 2,200-year continuum of geopolitical evolution. The county now governs 20 townships, 3 subdistrict offices, 375 administrative villages, and 70 urban communities, serving a population of 1.13 million. Spanning 103.3 kilometers at its maximum east-west width and 44.5 kilometers north-south length, it covers a total area of 2,614 square kilometers with a population density of 417 people per square kilometer.

Hengnan has been celebrated as a land of extraordinary talents throughout history. Its legacy shines through figures like Fu Xi, a polymath whose triple mastery of poetry, calligraphy, and painting earned him the epithet "Threefold Excellence," coupled with his scholarly expertise in epigraphy and bronze antiquities. The medical realm was graced by Jiang Yuxuan, author of the seminal Yixue Ge Kuo (Medical Rhymed Formulas) – a six-volume medical compendium spanning 200,000 characters that systematized therapeutic knowledge through poetic mnemonics. In the calligraphic arts, Xiao Qian revolutionized tradition through his philosophy of "capturing the essence beyond form," executing swift and vigorous brushstrokes reminiscent of a diving falcon seizing prey, ultimately forging a unique aesthetic school that transcended conventional styles. Hengnan's legacy of excellence extends to modern times with luminaries like Li Sen, the trailblazing sprinter who made history as China's first female Olympian competing in overseas Games; He Lianyu, who has been appointed as the Chief Auditor and Comptroller at Food and Agriculture Organization of the United Nations (FAO) headquarters; Luo Fu, known as the " Obsessive Poetry Master". There are also revolutionaries such as Xie Jin, who was called "Hunan's Standard-Bearer" by Mao Zedong, as well as revolutionaries Liao Huanxing and Wang Qiu.

Hengnan County captivates with its picturesque landscapes and extraordinary cultural heritage. To the east lie three karst caves—Chuankou, Maiyuan, and Sangtian—featuring jagged rock formations and surreal scenery, alongside the vast expanse of Longxi Lake. To the south lies the Jiangkou Bird Islet, where verdant forests resonate with the harmonious chorus of myriad birds. To the west stands Qishan Mountain, one of the 72 Peaks of Mount Heng (Nanyue), distinguished by towering bamboo groves and ancient trees reaching skyward. Midway up its slopes sits Renrui Temple, a revered Buddhist sanctuary in southern Hunan, housing an imperially bestowed plaque from Emperor Guangxu (1875-1908) of the Qing Dynasty. Notably, Jiangkou Bird Island and Qishan Renrui Temple are nationally certified 3A-level tourist attractions. Additionally, the Wang Family Ancestral Hall, honored as "Hengyang’s Premier Ancestral Shrine," holds the status of a National Cultural Heritage Protection Site.

Hengnan enjoys a strategic geographical position. It historically serving as the Southern Gateway to the Lingnan Corridor (ancient Baiyue territories encompassing modern Guangdong-Guangxi) and the Northern Threshold to the Chu Heartlands (core zones of Hunan-Hubei during the Three Chu period). Its terrain uniquely embraces three sides of downtown Hengyang, forming a natural urban buffer. Hengnan's transportation network forms a robust east-west and north-south matrix. Spanning east-west are the Hunan-Guangxi Railway, Hengyang-Chaling-Ji'an Railway, and Hengyang-Kunming Expressway, while north-south arteries include the Beijing-Guangzhou Double-track Railway, Beijing-Guangzhou High-Speed Railway, Yueyang-Linzhou High-Speed Railway, and Beijing-Zhuhai Expressway. National Highways 107 and 322 traverse the county, complemented by Provincial Highways 214 and 316 extending through surrounding areas. Water transport thrives via the year-round navigable Xiangjiang, Leishui, Chongling, and Zhengshui Rivers. Meanwhile, Hengyang Nanyue Airport, situated within the county, completes this tri-modal transport network integrating water, land, and air connectivity, solidifying Hengnan's role as a regional logistics nexus.

Hengnan sustains dynamic development across sectors. Renowned as "a land of milk and honey," it holds national accolades including "Top 100 Grain-Producing County," "National Advanced County for Agricultural Development," "National Base for Lean Pork Production," "National Model County for Water Conservancy," and "National Exemplar for Villager Self-Governance." The county boasts over 30 proven mineral resources, such as tungsten, manganese, lead, copper, iron, uranium, aluminum, gold, coal, fluorite, barite, mirabilite, potassium feldspar, and agate. Its fluorite reserves, celebrated globally for their high quality and abundance, are particularly notable. Hengnan boasts a robust industrial foundation, having established five pillar industries: metallurgy & chemical engineering, electronic information technology, machinery & equipment manufacturing, construction materials production, and agricultural byproduct processing.