The Ogallala Aquifer is a shallow water table aquifer located beneath the Great Plains in the United States. One of the world's largest aquifers, it underlies an area of approximately 174,000 mi² (450,000 km²) in portions of eight states: (South Dakota, Nebraska, Wyoming, Colorado, Kansas, Oklahoma, New Mexico, and Texas). It was named in 1898 by N.H. Darton from its type locality near the town of Ogallala, Nebraska.