Experts say the finds at the bottom of defensive walls at Castell Henllys in Pembrokeshire, reveal the talents of our ancestors.
Archaeologists believe the pickaxes were the main tools used to build huge ramparts, with thousands of tonnes of material being moved in the process.
The tools were found by students from York University, which has been conducting a summer dig at Castell Henllys for 21 years.
Dr Harold Mytum, who is directing the work, said: "The location of the pickaxes is very significant - suggesting they were discarded when the work was completed, possibly for a ritual purpose.
"Animal bones were also found, most likely the remnants of meals."
The relics will be taken to York for further analysis.
Site manager Phil Bennett said these finds had explained a lot about the people who had used the tools.
Sophistication
He said: "These help to bring the site alive.
"We can imagine Iron Age people some 2,500 years ago working on the ramparts using these simple and primitive, but very effective, tools.
"We have reconstructed some antler pickaxes and they work extremely well - another example of the sophistication and talent of the Iron Age people."
Castell Henllys has been owned and operated by the Pembrokeshire Coast National Park Authority since 1991.
It is the only Iron Age settlement in the UK to be reconstructed on a genuine archaeological site dating from that period.