The desert biome is found in northern Africa, western North America, western Asia, the center of Australia, and on the west coast of South America. Many mountain ranges influence deserts because they are so tall and wide. They do not let much rain get into the desert. If you look on a map you will see that there is a desert next to the Rocky Mountains in the United States, and a desert next to the Andes in South America.
Wind is also another way deserts form.
The wind that blows in the desert comes from far away waters. As it is travels, the moistness leaves. By the time any wind reaches the desert, it is very dry. Wind also helps in the formation of sand dunes. Sand dunes are huge piles of sand blown there by strong gusts wind.