A large, historic, health-oriented mineral springs resort, The Greenbrier, occupies 2,600 ha (6,500 acres) in an upland valley of the Allegheny Mountains near the West Virginia-Virginia border in the eastern U.S. Natural mineral water at 17C (62.5F) and with a high sulfate content is piped to individual soaking tubs of the mineral-bath wing, where it is heated by electricity to the desired temperature. Tubs are drained and filled after each use, so no chemical treatment is required. Water from a fresh-water spring is piped to an outdoor pool and the Grand Indoor Pool, where it is treated with chlorine and heated by steam. Thus, this mineral spring is not really geothermal, but has a two-century history of use by a spa resort