Olorgesailie is the site of people from the Acheulian or hand-axe culture. A variety of tools have been found at Olorgesailie including hand axes and other stone tools such as cleavers for skinning animals, heavy axes for digging, and round ball like tools used for crushing bone or hurling. Thousands of the uncovered tools have been left undisturbed under protective roofs.

The area was originally discovered in 1919 and then excavated by Louis and Mary Leakey in the 1940s. Fossilized skeletons of extinct forms of baboon, hippo, elephant, zebra and giraffe were found but to date there are no human remains. The most interesting find is the leg bone of a gigantic elephant that dwarfs the bone of a modern elephant Originally Olorgesailie was thought to be half a million years old but the site has recently been redated placing it between 750,000-1 million years ago.