The Ogallala Aquifer, also known as the High Plains Aquifer, is a vast yet shallow unerground water table aquifer located beneath the Great Plains in the United States. One of the world's largest aquifers, it lies under about 174,000 mi² (450,000 km²) in portions of the eight states of South Dakota, Nebraska, Wyoming, Colorado, Kansas, Oklahoma, New Mexico, and Texas. It was named in 1899 by N.H. Darton from its type locality near the town of Ogallala, Nebraska. About 27 percent of the irrigated land in the United States overlies this aquifer system, which yields about 30 percent of the nation's ground water used for irrigation. In addition, the aquifer system provides drinking water to 82 percent of the people who live within the aquifer boundary.