Hot Springs Reservation was initially created by an act of the United States Congress on April 20, 1832, to be preserved for future recreation.

Established before the concept of a national park existed, it was the first time that land had been set aside by the federal government to preserve its use as an area for recreation.

The hot spring water has been popularly believed for centuries to possess medicinal properties, and was a subject of legend among several Native American tribes.

Incorporated January 10, 1851, the city was known in the early 20th century as the home to Major League Baseball spring training, illegal gambling, speakeasies during the Prohibition era, and gangsters such as Al Capone, horse racing at Oaklawn Park, the Army and Navy Hospital, and 42nd President Bill Clinton.

Members of many Native American tribes had been gathering in the valley for over 8,000 years to enjoy the healing properties of the thermal springs.

In December 1804 William Dunbar and George Hunter made an expedition to the Ouachita Mountains and the springs at the request of President Thomas Jefferson, to study the native peoples and flora and fauna.

After he regained his health following two years of bathing in the hot water and eating local foods, he returned home to his plantation on the Red River in Louisiana.

On August 24, 1818, the Quapaw Indians ceded the land around the hot springs to the United States in a treaty after having been forced to a reservation south of the site.

[8] The first bathhouses were little more than brush huts and log cabins placed over excavations cut in the rocks to receive hot water that flowed from the springs.

[4][8][11] The earliest bathing procedure consisted of merely reclining in natural pools of hot springs and cool creek water for long periods of time.

The blanket-covered customer then would walk briskly back to their quarters to lie down for at least a half-hour to let the body recover its normal temperature.

The charges for the services of the attendants are the same and include the necessities except towels, blankets, bathrobes, laundering, rubbing mercury, and handling of invalids.

It was administered by the War Department for the benefit of military members, officers of the Public Health Service, and honorably discharged veterans.

Admission to the hospital was reserved for cases "of a serious and obstinate character, which, though resisting ordinary methods of relief, were promised a rapid and permanent recovery from the use of the waters of the spring.

[15] In November 1864 during the American Civil War, a large part of "the valley" (the central portion of the city along Hot Springs Creek) was burned - presumably by Union troops.

On March 5, 1878, a large fire burned for eight hours in the city, claiming nearly 150 buildings, including hotels, bath houses, and restaurants.

On February 26, 1905, a fire started in the Grand Central Hotel on Chapel Street and burned 25 blocks of the southern section of Hot Springs.

On September 5, 1913, a laundry worker was ironing and accidentally started a fire at 424 Church Street, which spread rapidly due to strong winds and burned nearly 60 blocks of the south part of the city.

A lightning strike during the storm caused a fire that destroyed several commercial businesses in downtown Hot Springs.

On February 15, 1956, a severe flood filled Central Avenue with three feet of rushing water, causing significant property damage.

[4] The Government Free Bathhouse was a concrete building fully equipped for bathing large numbers of people under sanitary conditions.

[4] The Park Service reminded people that they had to provide their own board and lodging and to have return travel fare, due to many destitute invalids who arrived each year in the mistaken belief that there was a public institution at which they would be cared for free of charge.

According to the United States Department of Agriculture, the Plant Hardiness zone at Hot Springs National Park Visitor Center at 627 ft (191 m) elevation is 7b with an average annual extreme minimum temperature of 9.5 °F (-12.5 °C).

Present day fauna include white-tailed deer, wild turkey, squirrel, rabbit, Virginia opossum, gray fox, coyote, skunk, raccoon, gopher, long-tailed weasel, mink, rat, chipmunk, frog, and nine-banded armadillo.

Under artesian pressure, the thermal waters rise and emerge through the Hot Springs Sandstone between the traces of two thrust faults, along several northeast-trending lineaments.

The composition of the water indicates it is heated rainwater which has not approached a magmatic source, so no volcanic action is involved in the formation of these hot springs.

[4] The thermal springs emerge from the plunging crest line of a large overturned anticline in the Zigzag Mountains of the Ouachita anticlinorium.

There are two recognized major thrust faults trending nearly parallel to fold axes that define the northern and southern limits of the thermal springs discharge area.

The southern fault extends northeastward about 9,000 ft (2,700 m) roughly along the axis of the Hot Springs anticline, and dips about 44 degrees north.

[26] Dissolved minerals in the water precipitate to form the white to tan travertine or "tufa rock" seen near the openings of the hot springs.