Pehistoric animals roamed Collingsworth County thousands of years ago. The Collingsworth County Museum has on display a mammoth tusk found on the Salt Fork of Red River and a mammoth jaw bone found in Collingsworth County in 1965.

The May 12, 1938, issue of The Wellington Leader reported a huge skull being found on a farm a few miles north and east of Wellington. The skull measured 32-1/2 inches between the eye sockets, 43 inches long, and weighed about 350 pounds. The skull was given to the Panhandle Plains Historical Museum in Canyon, Texas. Fossil rocks have been found in gravel pits at various locations around Collingsworth County.

Frederick W. Rathjen states in his book, The Texas Panhandle Frontier, that there are archaic sites in the counties of Hall and Donley both of which join Collingsworth County. Rathjen dates the Archaic Period from about 4000 BC to about 0.