Every hot spring on this site, plotted over a map of the heat rising through the ground. The warm colors mark where heat from deep in the earth reaches the surface fastest, and the springs crowd into them.
1,596
springs with heat flow data
102
median heat flow, mW/m²
1.6×
the US average of 65
257
hottest ground, mW/m²
Water
Getting there
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Showing all 1,723 springs
Tap a pin for the spring's water temperature and heat flow. Alaska and Hawaii springs are on the map without a heat flow value.
Why
Why Hot Springs Crowd Into the West
Heat flow measures how much warmth works its way up from deep inside the earth, in milliwatts per square meter. Across the United States it averages about 65.
Most of the West runs well above that. The crust there has been stretched thin and broken by faults, which leaves hot rock closer to the surface. Rain and snowmelt sink down through those cracks and come back up hot.
The cool blue East has only a scattering of springs. Most of them, like the ones in Hot Springs, Arkansas, and Warm Springs, Virginia, come from water that circulates unusually deep before it surfaces.
By state
Heat Flow Under Each State's Springs
Median heat flow at the springs in each state. The dashed line marks the US average of 65.
Seen from space
Geothermal Heat From Orbit
Landsat's thermal camera reads the temperature of the ground from about 440 miles up. On a clear winter day the biggest geothermal areas glow against the frozen land around them. Each card pairs a photo of the spring, or an aerial view where there's no good photo, with what the thermal camera saw.
Photo
Thermal · Landsat
Midway Geyser Basin, home of Grand Prismatic Spring. The bright thread running through it is the Firehole River, which hot runoff keeps free of ice all winter.
Photo: Michael Gäbler, CC BY 3.0
Photo
Thermal · Landsat
Two hot spots mark Imperial and Spray Geysers, tucked into the forest west of the Firehole in Lower Geyser Basin.
Photo
Thermal · Landsat
Norris Geyser Basin is the hottest in Yellowstone, and the whole basin glows through the snow.
Photo
Thermal · Landsat
Hot springs boil up in the bed of Hot Creek, so the stream below them stays warm and shows up as a glowing ribbon through the snow.
Aerial · USGS
Thermal · Landsat
Casa Diablo sits beside a geothermal power plant near Mammoth Lakes. The steaming ground and the plant show up as separate hot spots.
Photo
Thermal · Landsat
A lake of hot water and boiling mud in Lassen Volcanic National Park. It stays near 125°F all year, warm enough to glow as one bright spot in a snowbound valley.
Heat flow: Stanford Thermal Earth Model (Aljubran & Horne, 2024), CC BY 4.0. It covers the lower 48 states. Download the data (CSV), free to reuse under CC BY 4.0 with credit to Soaking Springs and the Stanford Thermal Earth Model. Thermal views: Landsat 8/9 surface temperature, USGS (public domain), via Microsoft Planetary Computer. Aerial views: USGS The National Map (public domain). Photos: Wikimedia Commons, credited on each card.