The Sahara Desert is a vast desert in North Africa, the West portion of the broad belt of parched land that extends from the Atlantic Ocean eastward past the Red Sea to Iraq. The entire desert, As the largest desert in the world, the Sahara is about 1600 km wide and 5000 km long from East to West. The total domain of the Sahara Desert is more than 9,000,000 sq. km, or more than 3,500,000 square miles. Around 80,000 square miles of the Sahara consists of partially fertile oases.

The limits of the Sahara Desert are the Atlantic Ocean in the West, the Mediterranean Sea in the North, the Red Sea in the East, and the Atlas Mountains in the South. The boundaries, however, are not clearly defined, and have been shifting for a thousand years. The Sahara was once a fertile area; millet and other grains were cultivated over 8,000 years ago. As conditions progressively became drier, however, farmers abandoned their land.

The Libyan Desert is in the East. The West Sahara Desert is an area of rock-strewn plains and sand deserts of varying elevation. The land is presently almost entirely without rainfall or surface water but possesses a number of underground rivers that flow fast from the Atlas and other mountains. Occasionally, the waters of these rivers find their way seeping to the surface; in these naturally irrigated oases, plants grow freely. The soil of this region of the Sahara is highly fertile and, where irrigation is possible, produces excellent crops.