An endoreheic basin is a closed drainage basin where water does not flow out to the ocean or sea. Instead, any water that enters the basin, through rivers or rainfall, either evaporates or seeps into the ground. This leads to the accumulation of water in lakes or salt flats, often resulting in high salinity levels due to evaporation. These basins can be found in various regions around the world, such as the Great Basin in the United States and the Caspian Sea area. They play a crucial role in local ecosystems and can influence climate patterns due to their unique hydrological characteristics.