Dasht-e Kavir, also known as the Great Salt Desert, is one of the two major deserts of Iran. It covers approximately 77,000 square kilometres in north-central Iran. The terrain consists of salt marshes, mudflats, and sand dunes and is largely impassable.

The Dasht-e Kavir has been a barrier and a mystery throughout Iranian history. Its salt crusts, treacherous mud beneath the surface, and extreme temperatures made crossing almost impossible without local knowledge. Caravans avoided the interior and traced routes around the edges, connecting Tehran, Isfahan, and Khorasan through the oasis towns of Qom, Kashan, and Semnan on the northern and western margins. The desert’s isolation made it a natural boundary between the settled plateau cities and the nomadic and semi-nomadic populations of the east. No major empire made systematic use of the interior; it was simply avoided.

The Dasht-e Kavir today is sparsely inhabited. Its eastern and southern margins contain small oasis settlements sustained by qanats. The desert is used for military testing and has strategic significance as a vast unpopulated buffer zone. Climate change is expanding the desert’s effective boundary as aquifer depletion reduces the extent of irrigated agriculture on its margins. Salt dust storms from the dried surfaces of seasonal lakes within the desert are an increasing environmental problem for surrounding provinces.