How the data is built

Name: Every Hot Spring U.S. hot springs dataset
Creator: Every Hot Spring
License: https://opendatacommons.org/licenses/odbl/1-0/

Every Hot Spring lists 2,150 named hot springs in 26 states. The dataset was last rebuilt on October 11, 2026. This page explains where every field comes from, so you can judge how far to trust it.

The short version

Locations and temperatures come from public survey data, mainly the NOAA NCEI thermal springs list.
Names, towns, websites and access tags are merged in from OpenStreetMap, Wikidata and Wikipedia.
Access, fees, clothing policy and closures are added by hand only when an official or operator source says so, and that source is linked on the spring's page.
When no source states a fact, the page says "Not recorded". Nothing is guessed or inferred.
No listing has yet been checked on site by a person. Treat everything here as a starting point and confirm with the land manager.

Sources

NOAA NCEI Thermal Springs List (archived copy, NCEI accession 0303600). The U.S. government survey of thermal springs, with coordinates and maximum surface temperatures. NOAA retired the live dataset in May 2025, so it will not be updated. Public domain.
OpenStreetMap. Mapped hot springs with names and, where mappers recorded them, access, fee and nudity tags. Data © OpenStreetMap contributors, Open Database License.
Wikidata. Structured records for named springs: county, coordinates, official website. CC0.
Wikipedia. The first one or two sentences of a spring's article, used as its description. CC BY-SA 4.0.
U.S. Census Bureau cartographic boundaries(2010, 1:5M). Used only to place each spring in the right state.
Official pages from the USDA Forest Service, Bureau of Land Management, National Park Service, state parks and tourism offices, and resort operators. Used for access, fees, clothing policy, nearest town and closures, and linked under "Checked against" on each spring's page.

Commercial hot spring guides are not copied. Where a state guide used one to locate information, it is listed in that guide's sources so you can see where a claim came from.

How records are merged

The same spring often appears in several sources under slightly different names. Records are merged when they share an explicit identifier (an OpenStreetMap feature tagged with a Wikidata or Wikipedia link), when their normalized names match within 500 meters, or when the same distinctive name appears in two sources within 3 kilometers in the same state. Coordinates prefer OpenStreetMap, then Wikidata, then NCEI. Temperatures prefer NCEI measurements.

NCEI records with no name at all are kept in the dataset but do not get a page, because there is nothing to search for and nothing to say about them.

What the fields mean

Source temperature is the hottest recorded reading at the spring's outlet, not a soaking pool. 1,375 springs have one.
Access says who controls the land as last recorded: public land, a resort or commercial operation, or private property. It is not a promise that you can enter today. 456 springs have it recorded.
Type describes the facility: primitive (undeveloped pools), developed pools without lodging, or a resort.
Fee and clothing optional are filled only from an OpenStreetMap tag or a cited source.
Nearby springs and the drive-time bands on city pages use straight-line distance, which can be far shorter than the drive.

Closures

307 springs are marked "Not open for soaking". Most are thermal features in Yellowstone National Park, where federal regulations prohibit bathing in water of entirely thermal origin (36 CFR 7.13). Others are closed resorts or posted private land. Each closure links to the source that documents it.

Hand research

484 springs carry facts added by hand from official sources. That research is stored separately from the merged survey data and layered on last, so rebuilding from the public sources never erases it.

Which pages appear in search

Every named spring has a page, so the map and state lists are complete. Many are little more than a name and coordinates from a decades-old survey, or share a generic name like "Warm Spring" with dozens of others. Those 1,398 pages ask search engines not to index them until a source adds something useful. Right now 752 of 2,150 spring pages are indexed. A page is indexed when it has a written guide, a Wikipedia article, a cited official source, a recorded access, fee, town or website, or a distinctive name with a measured temperature and a county.

Using the data

A list of every spring's name, coordinates, source temperature and page is published at/springs.json. Because it includes OpenStreetMap data, it is offered under the Open Database License; please credit Every Hot Spring and OpenStreetMap contributors.