tl;dr a team including David Bustos published a paper describing their analysis of the age of fossilized footprints in NM White Sands National Park by carbon dating seeds above and below the footprints. This pegs the footprints left in former marshland mud as dating between 2.3e5 and 3.1e5 years old. This lends firmer credence to theories of migration to the american continents at or before the inception of the Bering Strait land bridge (as opposed to stone tools which are harder to date or distinguish from accidental artifacts).