Largest polar desert is Antarctic Polar Desert covers the continent of Antarctica and has a size of about 5.5 million square miles and largest non-polar desert is the Sahara Desert desert in northern Africa. It covers a surface area of about 3.5 million ... moreLargest polar desert is Antarctic Polar Desert covers the continent of Antarctica and has a size of about 5.5 million square miles and largest non-polar desert is the Sahara Desert desert in northern Africa. It covers a surface area of about 3.5 million square miles