PEOPLING

Footprints Across America

~23,000 to 21,000 years ago

Palaeolithic · Upper Palaeolithic · Last glacial · Last Glacial Maximum

Pressed into the shore of a vanished lake at White Sands, New Mexico, human footprints, many of them left by children and teenagers, date to the height of the last ice age, 23,000 to 21,000 years ago, when ice sheets sealed the routes from Asia. People were therefore already deep inside the Americas before the corridors opened; their tracks run alongside those of mammoths and giant ground sloths.

Why it matters

The last continents to be peopled had their date pushed back by walking children. White Sands precedes every accepted archaeological culture in the Americas by millennia, and it requires an arrival before the glacial gates closed, or through a coastal door. A footprint is also evidence of a kind no stone tool can be: a person, of a certain size, moving at a certain pace, one afternoon.

Dating & uncertainty

Radiocarbon on aquatic seeds bracketing the prints gave 23,000 to 21,000 years; critics invoked old-carbon effects. Radiocarbon on terrestrial pollen from the same layers, luminescence on the sediments, and then the stratigraphy of the ancient lake itself all returned the same answer. The footprints are as dated as footprints can be.

Sources

1. Bennett et al. (2021), Science · Evidence of humans in North America during the Last Glacial Maximumdoi:10.1126/science.abg7586
2. Pigati et al. (2023), Science · Independent age estimates resolve the controversy of ancient human footprints at White Sandsdoi:10.1126/science.adh5007
3. Holliday et al. (2025), Science Advances · Paleolake geochronology supports Last Glacial Maximum (LGM) age for human tracks at White Sands, New Mexicodoi:10.1126/sciadv.adv4951

Our species’ history as one day

22:19:251 h 41 min before midnight

if the 315,000 years of Homo sapiens were compressed into a single day