An aquifer is a natural underground layer of water-bearing rock or sediment that can store and transmit groundwater. These formations are crucial for supplying fresh water to wells, springs, and rivers. Aquifers can be found in various geological settings and are essential for agricultural, industrial, and domestic water use. Aquifers are replenished through precipitation and surface water infiltration. They can be classified into two main types: confined aquifers, which are trapped between impermeable layers, and unconfined aquifers, which are open to the surface. Proper management of aquifers is vital to ensure sustainable water resources for future generations.