The Badain Jaran Desert (巴丹吉林沙漠) is a desert in China which spans the provinces of Gansu, Ningxia and Inner Mongolia. It covers an area of 49,000 square kilometres (19,000 sq mi). By size it is the third largest desert in China.
This desert is home to some of the tallest stationary dunes on Earth, with some reaching a height of more than 500 meters (1,600 ft), although most average at around 200 meters (660 ft). Its tallest dune is also measured, from base to peak, as the world's third tallest dune and highest stationary dune in the world.
The desert also features over 100 spring-fed lakes that lie between the dunes, some of which are fresh water while others are extremely saline. These lakes give the desert its name which is Mongolian for "mysterious lakes". It is also crossed by one river, the Ruo Shui ("weak water"), which has formed an alluvial plain in the desert.