[1] Longnan is in southern Gansu province bordering Shaanxi in the east and Sichuan in the south.

Longnan has a temperate, monsoon-influenced semi-arid climate (Köppen BSk/BSh, depending on the source definition), with cool and very dry winters and hot, moderately humid summers.

With monthly percent possible sunshine ranging from 34% in September and October to 53% in December, the city receives 1,850 sunlight hours annually.

Between 5000 and 6000 years ago, civilizations developed along the Xihan ("Western Han") and Bailong ("White Dragon") rivers.

Longnan is very important in Chinese history: it was the home of Rong tribes that troubled the Shang and Zhou dynasties and is considered the homeland of the House of Ying, the family of the Qin dynasty that united China at the end of the Warring States period.

Under imperial Chinese rule, the area was administered as Jie Prefecture (t 階州, s 阶州, Jiēzhōu).

Coal, copper, lead, zinc, petroleum, and gold are all major mineral resources for Longnan.