(See correction below.)

Much older.

T̶h̶e̶r̶e̶ ̶a̶r̶e̶ ̶v̶a̶r̶i̶o̶u̶s̶ ̶d̶i̶s̶p̶u̶t̶e̶d̶ ̶s̶i̶t̶e̶s̶,̶ ̶b̶u̶t̶ ̶t̶h̶e̶ ̶r̶e̶c̶e̶n̶t̶ ̶d̶i̶s̶c̶o̶v̶e̶r̶y̶ ̶o̶f̶ ̶f̶o̶o̶t̶p̶r̶i̶n̶t̶s̶ ̶i̶n̶ ̶W̶h̶i̶t̶e̶ ̶S̶a̶n̶d̶s̶ ̶e̶s̶t̶a̶b̶l̶i̶s̶h̶e̶s̶ ̶a̶ ̶l̶o̶w̶e̶r̶ ̶b̶o̶u̶n̶d̶ ̶o̶f̶ ̶b̶e̶t̶w̶e̶e̶n̶ ̶2̶1̶k̶ ̶a̶n̶d̶ ̶2̶3̶k̶.̶ (This is less settled than I'd thought.)

https://en.wikipedia.org/wiki/White_Sands_fossil_footprints

T̶h̶e̶ ̶p̶r̶e̶v̶i̶o̶u̶s̶ ̶u̶n̶c̶o̶n̶t̶r̶o̶v̶e̶r̶s̶i̶a̶l̶ ̶l̶o̶w̶e̶r̶ ̶b̶o̶u̶n̶d̶ ̶w̶a̶s̶ ̶b̶e̶t̶w̶e̶e̶n̶ ̶1̶2̶.̶8̶k̶ ̶a̶n̶d̶ ̶1̶3̶.̶5̶k̶.̶ (This hasn't been a lower bound for a while, see below.)

https://en.wikipedia.org/wiki/Clovis_point

It's my understanding this is an active area of debate. To give a tentative upper bound, the Cerutti mastodon kill - who's anthropogenic origins, while they seem compelling to me (a nonexpert), are hotly debated, have a date of 130k years ago.

https://en.wikipedia.org/wiki/Cerutti_Mastodon_site

(I suspect GP meant to reference the Cerutti Mastodon site, rather than Serpent Mound?)

(And of course, much of this is referenced in the article, I'm busted for reading the comments first! Interesting article that says it far better than I, worth reading.)