77°28′S 162°31′E / 77.467°S 162.517°E
The McMurdo Dry Valleys are a series of largely snow-free desert valleys on the continental coastline of Victoria Land, Antarctica, east of the East Antarctic Ice Sheet and west of McMurdo Sound and the Ross Sea. The Dry Valleys are notable for being the coldest and driest desert in the world, as well as being the largest ice-free region in Antarctica; as a result, the Valleys have become a notable hotbed for scientific research in the Antarctic region. The Dry Valleys' unique climate is due to their location nestled within the Transantarctic Mountains along with high-pressure katabatic winds that scour away snowfall and humidity across the region. Surrounding mountains prevent the flow of ice from nearby glaciers. The region's geology is primarily granites and gneisses, and glacial tills dot the bedrock landscape, with loose gravel covering the ground. The Valleys are one of the driest places on Earth, though there are several anecdotal accounts of rainfall within the Dry Valleys.