.Yunnan, also named as Dian for short, is situated in the Southwest frontier of China. Stretching about 865 kilometers from east to west and 990 kilometers from north to south, it covers an area of 394,000 square kilometers. Accounting for 4.1 percent of the total land area of China, it is the 8th largest province in China; with Kunming being its capital city; Yunnan has 8 municipalities and 8 minority autonomous prefectures under jurisdiction altogether. Yunnan is also situated in the southwestern part of the Yunnan-Guizhou Plateau. It borders on Guizhou Province and Guangxi Zhuang Autonomous Region in the southeast, Sichuan Province in the northeast and Tibet Autonomous Region in the northwest. In its west and south Yunnan shares a common border with Myanmar, Laos and Vietnam along a total boundary of 4,060 kilometers. In the bordering area, there are 12 national border ports, 8 provincial border ports, and over 90 routes leading into the neighboring countries. In addition, Yunnan is geographically proximate to Thailand, Cambodia, Bangladesh and India. Since ancient times, Yunnan has been serving as China's gateway to Southeast Asia and South Asia and is a convergence for oriental and western cultures. The Southern Silk Road which existed 2,000 years ago started its journey from Sichuan to Yunnan, and extended from Yunnan further down to Southeast Asia, Central Asia, the Arabia region, and the West.

Yunnan is at the far eastern edge of the Himalayan uplift, and was pushed up in the Pleistocene, primarily in the Middle Pleistocene, although the uplift continues into the present. The eastern part of the province is a limestone plateau with karst topography and unnavigable rivers flowing through deep mountain gorges. The main surface formations of the plateau are the Lower Permian Maokou Formation, characterized by thick limestone deposits, the Lower Permian Qixia Formation, characterised by dolomitic limestones and dolostones, the Upper Permian basalts of the Ermeishan Formation (formerly Omeishan plateau basalts), and the red sandstones, mudstones, siltstones, and conglomerates of the Mesozoic–Paleogene, including the Lufeng Formation and the Lunan Group (Lumeiyi, Xiaotun, and Caijiacong formations). In this area is the noted Stone Forest or Shilin, eroded vertical pinnacles of limestone (Maokou Formation). In the eastern part the rivers generally run eastwards. The western half is characterized by mountain ranges and rivers running north and south.