Principal Deserts of the World Deserts are arid regions, generally receiving less than ten inches of precipitation a year, or regions where the potential evaporation rate is twice as great as the precipitation. The world's deserts are divided into four categories.Subtropical desertsare the hottest, with parched terrain and rapid evaporation. Althoughcool coastal desertsare located within the same latitudes as subtropical deserts, the average temperature is much cooler because of frigid offshore ocean currents.Cold winter desertsare marked by stark temperature differences from season to season, ranging from 100° F (38° C) in the summer to 10° F (–12° C) in the winter.Polar regionsare also considered to be deserts because nearly all moisture in these areas is locked up in the form of ice. DesertLocationSizeTopography SUBTROPICAL DESERTS SaharaMorocco, Western Sahara, Algeria, Tunisia, Libya, Egypt, Mauritania, Mali, Niger, Chad, Ethiopia, Eritrea, Somalia3.5 million sq. mi.70% gravel plains, sand, and dunes. Contrary to popular belief, the desert is only 30% sand. The world's largest nonpolar desert gets its name from the Arabic wordSahra', meaning desert ArabianSaudi Arabia, Kuwait, Qatar, United Arab Emirates, Oman, Yemen1 million sq. mi.Gravel plains, rocky highlands; one-fourth is the Rub al-Khali (“Empty Quarter”), the world's largest expanse of unbroken sand KalahariBotswana, South Africa, Namibia220,000 sq. mi.Sand sheets, longitudinal dunes Australian Desert Gibson Australia (southern portion of the Western Desert)120,000 sq. mi.Sandhills, gravel, grass. These three regions of desert are collectively referred to as the Great Western Desert—otherwise known as “the Outback.” Contains Ayers Rock, or Uluru, one of the world's largest monoliths Great Sandy Australia (northern portion of the Western Desert)150,000 sq. mi. Great Victoria Australia (southernmost portion of the Western Desert)250,000 sq. mi. Simpson and Sturt Stony Australia (eastern half of the continent)56,000 sq. mi.Simpson's straight, parallel sand dunes are the longest in the world—up to 125 mi. Encompasses the Stewart Stony Desert, named for the Australian explorer MojaveU.S.: Arizona, Colorado, Nevada, Utah, California54,000 sq. mi.Mountain chains, dry alkaline lake beds, calcium carbonate dunes SonoranU.S.: Arizona, California; Mexico120,000 sq. mi.Basins and plains bordered by mountain ridges; home to the Saguaro cactus ChihuahuanMexico; southwestern U.S.175,000 sq. mi.Shrub desert; largest in North America TharIndia, Pakistan175,000 sq. mi.Rocky sand and sand dunes COOL COASTAL DESERTS NamibAngola, Namibia, South Africa13,000 sq. mi.Gravel plains AtacamaChile54,000 sq. mi.Salt basins, sand, lava; world's driest desert COLD WINTER DESERTS Great BasinU.S.: Nevada, Oregon, Utah190,000 sq. mi.Mountain ridges, valleys, 1% sand dunes Colorado Plateau U.S.: Arizona, Colorado, New Mexico, Utah, Wyoming130,000 sq. mi.Sedimentary rock, mesas, and plateaus—includes the Grand Canyon and is also called the “Painted Desert” because of the spectacular colors in its rocks and canyons PatagonianArgentina260,000 sq. mi.Gravel plains, plateaus, basalt sheets Kara-Kum Uzbekistan, Turkmenistan135,000 sq. mi.90% gray layered sand—name means “black sand” Kyzyl-Kum Uzbekistan, Turkmenistan, Kazakhstan115,000 sq. mi.Sands, rock—name means “red sand” IranianIran100,000 sq. mi.Salt, gravel, rock TaklamakanChina105,000 sq. mi.Sand, dunes, gravel GobiChina, Mongolia500,000 sq. mi.Stony, sandy soil, steppes (dry grasslands) POLAR ArcticU.S., Canada, Greenland, Iceland, Norway, Sweden, Finland, Russia5.4 million sq. mi.Snow, glaciers, tundra AntarcticAntarctica5.5 million sq. mi.Ice, snow, bedrock