Methodology
Definitions on this page were last verified on 6 October 2026. Each
resort record also carries its own verifiedAt date for the
facts in that record.
Ownership tiers
Every listed ski area has one owner and one tier. The tier follows how many US ski areas that owner runs, not which pass the mountain sells.
- Independent
- The owner has one ski area, or the area is run by a co-op, a nonprofit, or a municipality.
- Small group
- The same owner runs 2 to 5 ski areas.
- Large group
- The same owner runs 6 or more ski areas. Regional companies such as Boyne, POWDR, and Mountain Capital Partners fall here when their count qualifies. They stay listed so you can filter them out yourself.
Vail and Alterra exclusion
A ski area is omitted when Vail Resorts or Alterra Mountain Company owns it or operates it, including mountains those companies run for someone else. An independently owned mountain that only sells Epic or Ikon partner tickets stays in, and the passes it accepts are shown.
Ownership changes. The exclusion list is re-checked against the companies' own resort lists, and a mistake should be reported so the record can be corrected.
Data sources
Facts are taken in this order, and each non-null value cites a URL:
- The resort's own website (trail map, stats, tickets, about page).
- The state ski association.
- OpenSkiMap, which is built from OpenStreetMap.
- Wikipedia, when a primary source is not available.
Map tiles come from OpenFreeMap. Resort locations are seeded from OpenSkiData and then checked by hand. We do not copy review text.
Unknown policy
If no source supports a value, the field is null and the site shows Unknown. We do not estimate vertical, price, terrain mix, or amenities. A guess is treated as an error, not as coverage. You can still include resorts that have unknown values when you filter the map.