Water in its liquid and gaseous states has always been the main reason for the development of Hot Springs in the Valley of Vapors. The water of the springs comes from rain which fell in mountains to the north and northeast over 4,000 years ago. Flowing through cracked rock at about one foot a year, the water migrates downward 4,500 to 7,500 feet, taking on minerals and the natural heat of the rocks at those depths. Pushed back up by artesian pressure along fault and fracture lines, the thermal springs surface in an area about 1,500 feet by 400 feet in a gap between Hot Springs Mountain and West Mountain. Having risen much more quickly than it descended, the water emerges at an average 143°F. Thirty-three of the 43 thermal springs currently flowing are collected into a central reservoir at a rate of 750,000 to 950,000 gallons a day, from which it is piped to free public taps within the National Park and sold to bathhouses and hotels.
Native peoples, who quarried novaculite for tools on the mountain at least 3,000 years ago, probably frequented the springs. Jean-Bernard Bossu noted during a stay with the Quapaw in 1771: “The Arkanças country is visited very often by western Indians who come here to take baths,” for the hot waters “are highly esteemed by native physicians who claim that they are so strengthening.” European settlers were also drawn to the hot springs for therapeutic baths to treat rheumatism and other ailments.
For more about the science of the springs click here.