Hot Springs is the 11th most populous city in the U.S. state of Arkansas, the county seat of Garland County, and the principal city of the Hot Springs Metropolitan Statistical Area encompassing all of Garland County. According to the 2010 United States Census, the population of the city was 35,193.

Hot Springs is traditionally best known for the natural spring water that gives it its name, flowing out of the ground at a temperature of 147 °F (64 °C) . Hot Springs National Park is the oldest federal reserve in the USA, and the tourist trade brought by the famous springs make it a very successful spa town. Since Hot Springs National Park was the oldest federal reserve, it was the first to receive its own US quarter in April 2010 as part of the America the Beautiful Quarters.

The city takes its name from the natural thermal water that flows from 47 springs on the western slope of Hot Springs Mountain in the historic downtown district of the city. About a million gallons of 143-degree^{[clarification needed]} water flow from the springs each day. The rate of flow is not affected by fluctuations in the rainfall in the area. Studies by National Park Service scientists have determined through carbon dating^{[clarification needed]} that the water that reaches the surface in Hot Springs fell as rainfall in an as-yet undetermined watershed 4,000 years earlier. The water percolates very slowly down through the earth’s surface until it reaches superheated areas deep in the crust and then rushes rapidly to the surface to emerge from the 47 hot springs.

Arkansas (ⁱ/ˈɑrkənsɔː/ AR-kən-saw) is a state located in the Southern region of the United States. Its name is an Algonquian name of the Quapaw Indians. Arkansas shares borders with six states (N: Missouri; E: Tennessee, Mississippi; S: Louisiana; SW: Texas; W: Oklahoma), and its eastern border is largely defined by the Mississippi River. Its diverse geography ranges from the mountainous regions of the Ozarks and the Ouachita Mountains, which make up the U.S. Interior Highlands, to the eastern lowlands along the Mississippi River. Arkansas is the 29th most extensive and the 32nd most populous of the 50 United States. The capital and most populous city is Little Rock, located in the central portion of the state.

The name “Arkansas” derives from the same root as the name for the state of Kansas. The Kansa tribe of Native Americans are closely associated with the Sioux tribes of the Great Plains. The word “Arkansas” itself is a French pronunciation (“Arcansas”) of a Quapaw (a related “Kaw” tribe) word, akakaze, meaning “land of downriver people” or the Sioux word akakaze meaning “people of the south wind”. The pronunciation of Arkansas was made official by an act of the state legislature in 1881, after a dispute between two U.S. Senators from Arkansas. One wanted to pronounce the name /ɑrˈkænzəs/ ar-KAN-zəs and the other wanted /ˈɑrkənsɔː/ AR-kən-saw.

A hot spring is a spring that is produced by the emergence of geothermally heated groundwater from the Earth's crust. There are geothermal hot springs in many locations all over the crust of the earth.

There is no universally accepted definition of a hot spring. For example, one can find the phrase hot spring defined as

The related term "warm spring" is defined as a spring with water temperature less than a hot spring by many sources, although Pentecost et al. (2003) suggest that the phrase "warm spring" is not useful and should be avoided. The US NOAA Geophysical Data Center defines a "warm spring" as a spring with water between 20 and 50 °C (68 and 122 °F).

The water issuing from a hot spring is heated by geothermal heat, i.e., heat from the Earth's mantle. In general, the temperature of rocks within the earth increases with depth. The rate of temperature increase with depth is known as the geothermal gradient. If water percolates deeply enough into the crust, it will be heated as it comes into contact with hot rocks. The water from hot springs in non-volcanic areas is heated in this manner.