While packs of wolves and grizzly bears were roaming through the forests near Wheatley, Stone Age man was using what is now a nature reserve as his hunting ground.
The evidence came from five flints, which have been identified by experts at Oxfordshire County Museum as microliths used in arrows, spears and harpoons.
They were found by John Tyler, a wildlife enthusiast and local volunteer for the Berkshire, Buckinghamshire and Oxfordshire Wildlife Trust, at the Sydlings Copse nature reserve. They are between 6,000 and 10,000 years old.
County archaeologist Paul Smith said: "It's always exciting to obtain new evidence of Mesolithic activity in Oxfordshire.
"The microliths would have been used by hunter gatherers to hunt deer, wild boar and game fowl.
"The flint points were perhaps left at a temporary campsite by a small band of hunters over an extensive territory that might have included the fenland of Otmoor as well as the rich game areas of the Thame and Thames river valleys."
Mr Tyler added: "When I picked up the flints I could see the wave-like markings where each one had been struck a bigger lump of flint.
"I was a bit cautious at first as I didn't want to get my hopes up, so I sent them to the museum and forgot about them until the identification came back."