Arkansas has no volcanoes, yet the springs of Hot Springs National Park reach the surface at an average of 143 degrees Fahrenheit, according to the National Park Service. The heat comes from the normal rise in temperature with depth. Rain falls on the Ouachita Mountains, a range folded and faulted when two tectonic plates collided about 300 million years ago, and seeps along fractures in the tilted rock to depths of 4,500 to 7,500 feet. After a journey the park puts at about 4,400 years, the heated water meets a fault and rises quickly to the surface at the base of Hot Springs Mountain, along what is now Bathhouse Row.
The springs are federal land and have been for a long time. Congress set aside the Hot Springs Reservation in 1832, and it became Hot Springs National Park in 1921. Today the National Park Service collects the water from the springs into a central system that supplies the historic bathhouses and a set of public fountains, where the park provides the spring water free of charge for filling jugs. The display spring behind Arlington Lawn and the hot water cascade on the lawn show the water at the surface. Beyond the park, the Ouachita National Forest covers much of the surrounding mountains, and the Arkansas Geological Survey maps the region.
Unlike western hot springs, the park sits inside a city and is reached by paved roads year-round, without seasonal pass closures. The park road up Hot Springs Mountain and the trails on the surrounding ridges lie at low elevation, where snow is rare. Individual fountains are occasionally closed for maintenance, and the park posts those closures on its website.
Source temperatures in Arkansas
Half of the 6 springs with a measurement are at 81°F or below at the source, and 1 reach 130°F or more. The hottest, Hot Springs, measured 147°F. These are the readings published by NOAA in the Thermal Springs List (about 1980); a spring can change over decades, and water cools quickly as it flows away from the vent.
All 6 springs in the NOAA list
Sorted from hottest to coolest. Many are on private land, in closed areas or are only small seeps; only the places listed above have checked access facts.
| Spring (NOAA name) | Source temp | °C | Lat, lon |
|---|---|---|---|
| Hot Springs | 147°F | 64 | 34.51, -93.05 |
| Caddo Gap Springs | 95°F | 35 | 34.38, -93.61 |
| Warm Springs | 82°F | 28 | 36.48, -91.05 |
| Big Chalybeate Spring | 79°F | 26 | 34.54, -93.02 |
| Spring on Redland Mountain | 77°F | 25 | 34.32, -93.74 |
| Spring on Little Missouri River | 74°F | 23 | 34.41, -93.91 |
Questions
How many hot springs are in Arkansas?
The NOAA Thermal Springs List names 6 thermal springs in Arkansas. Many are on private land or are small seeps; the list is a geological record from about 1980, not a list of places open to visitors.
What is the hottest spring in Arkansas?
Hot Springs, at 147°F (64°C) at the source in the NOAA list.
Who manages the public hot springs?
Public springs are usually on national forest, BLM or park land. Check the managing agency before a trip.
Sources: NOAA NCEI, Thermal Springs List for the United States (NCEI Accession 0303600, doi:10.25921/c8p0-zs06), public domain (CC0); state boundaries from the U.S. Census Bureau; access facts from the managing agencies, linked on each place page; geology and seasons: nps.gov, usgs.gov.
Data guide for trip planning. Conditions, access and rules change; check with the managing agency before you go.