Longnan is in southern Gansu province bordering Shaan Xi in the east and Sichuan in the south. It is called Gansu's southern gateway and China's gateway to the northwest. The major geographic features in Longnan are the Qinba Mountains in the east, the Loess Plateau in the north, and the Tibetan Plateau in the west. It is part of the Central Han basin in the east and the Sichuan basin in the south. Elevations range from 800 to 4200 meters above sea level. The three major rivers in Longnan are the Bailong, the Baishui, and the Jialing. Besides these major rivers there are more than 3800 streams and creeks. The annual flow from all of these rivers and streams is more than 28 billion m3.

Average temperatures for most of the area range between 10 ¡æ and 15 ¡æ. Annual precipitation is 400 to 1000 mm. There are between 160~280 frost free days. Annually, there are an average of 1,600 sunlight hours.

The area is 27,000 km2.