The work offers a systematic survey of the Sahara’s physical geography, examining its size, aridity, and climatic causes such as persistent high-pressure belts and latitude-driven precipitation patterns; it analyzes topography, geology, and variations between western, central, and eastern sectors, and discusses coastal and oceanic influences, mountain effects, and hydrology. It reviews the history and methods of exploration and scientific mapping that progressively clarified oasis regions and interior plateaus, and incorporates meteorological and geological evidence to explain dune fields, salt pans, and erosion processes, while outlining implications for human presence, vegetation, and potential development in the desert environment.