Methodology

We don't make numbers up. We don't round. We cite our sources.

Where the data comes from

• OpenStreetMap — base set of waterfall coordinates, names, occasional heights. Licensed under ODbL.
• USGS GNIS — canonical US names. Public domain.
• Wikidata + Wikipedia — descriptions, official heights, historical context. CC0 / CC-BY-SA.
• National Park Service — official descriptions and alerts inside park boundaries.
• Our own measurements — when we visit, Theo brings a hand level and tape. Marina photographs and notes. We mark those pages.

Why we use Class 1-5 instead of “easy/moderate/hard”

Because trail rating wheels are useless. We've done dozens of trails marked “moderate” that involved Class 3 scrambling, exposed cliff edges, or thigh-deep water crossings. Class 1-5 maps to terrain, not to crowd-sourced sentiment.

What we drop

We drop unnamed nodes. We drop falls we cannot confirm in at least two sources. We drop entries that turn out to be fenced-off industrial weirs. If you find one on the site that shouldn't be, email us with the slug.