The Ogallala is a vast underground aquifer located beneath the Great Plains of the United States. It stretches across eight states, including Nebraska, Kansas, and Texas, and is one of the largest aquifers in the world. The water from the Ogallala is crucial for agriculture, providing irrigation for crops in a region that receives limited rainfall. This aquifer was formed during the last Ice Age and contains ancient water that has been trapped for thousands of years. Over-extraction of water for farming and other uses has raised concerns about its sustainability, leading to efforts to manage and conserve this vital resource.