What is the largest artesian basin in the world?

The largest artesian basin in the world is Australia’s Great Artesian Basin. This enormous underground groundwater system extends across about 1.7 million square kilometres, covering roughly 22 percent of the Australian continent.

The basin lies beneath parts of Queensland, New South Wales, South Australia, and the Northern Territory. It consists of layers of porous sandstone that store groundwater, bounded by less-permeable rock. In an artesian system, pressure can force water upward through a bore without mechanical pumping, although many modern bores require careful management to maintain flow.

The Great Artesian Basin is especially important because it supplies water across much of inland Australia, where permanent surface water is scarce. Groundwater temperatures can be warm, and natural springs known as mound springs support distinctive plants and animals. It is sometimes confused with the Ogallala Aquifer, but the Ogallala is a major groundwater system in North America, not the world’s largest artesian basin.