The coastal sites tend to be associated with marine resources — shellfish, sea mammals, and fish — consistent with the coastal adaptation that the coastal route hypothesis predicts.

The dates from these sites range from roughly 13,000 to 16,000 years ago, with some sites potentially even older.

From the interior of North America, sites like Buttermilk Creek in Texas have produced evidence — in the form of stone artifacts found in stratigraphic contexts that underlie Clovis materials — for human presence before the Clovis horizon.

The Buttermilk Creek evidence is important because the stone tools found below the Clovis levels are not themselves Clovis tools, suggesting that Clovis technology was not the first stone tool technology used in North America.

From South America, Monte Verde in Chile remains the most securely dated and widely accepted pre-Clovis site.