Our methodology: how we compile this data

We haven't visited these places ourselves, and every page says so rather than implying otherwise. Details are compiled from public land-manager, USGS and NOAA sources and cross-checked where possible; conditions, access rules and fees change without notice, so confirm with the managing agency before you go.

Sources by category

Hot springs

NOAA/NCEI Thermal Springs List for the United States (1980), archived via PANGAEA — source. Temperatures are a historical estimate from the 1980 base survey, not a current reading.

Waterfalls

USGS Geographic Names Information System (GNIS), "Falls" feature class — source. Public-domain federal gazetteer data; confirms a named feature exists and its coordinates, not current trail conditions or access rules.

Swimming holes

No state or federal register exists for swimming holes. This list is hand-compiled from public park-service pages and other open sources, not a government dataset.

What a listing does and doesn't confirm

A record on this site confirms that a named feature exists at a set of coordinates, per a government source, checked on the date shown. It does not confirm current legal access, fees, trail conditions, water quality or crowding — those change faster than any dataset, so we mark them "requires confirmation" wherever our sources don't give a clear, current answer, rather than guessing.

Editorial picks vs. the full dataset

Each state page's write-up highlights a curated shortlist, not the entire dataset — the full-dataset table on every state page is there for reference and transparency, not as a recommendation. A place appearing in the full dataset table does not mean we endorse visiting it; some entries are on private land, permit-only, or currently closed.