The National Museums Liverpool Field Archaeology Unit was performing excavations as part of the M62's £38M junction 6 improvement scheme near Huyton, when the discovery was made.
The artefacts found date from the Mesolithic to the Bronze Age periods, between 5000 to 2000 BC, and include burnt hazelnuts and flints which historians say indicates activity of hunter-gatherer tribes in the area.
The Highways Agency's project manager, Gary Hilton, commented: "The Highways Agency takes its responsibility for our heritage very seriously and we are delighted to have found this window into the past. Lots of people are very excited by what has been discovered here."
The excavation has also uncovered examples of Roman made pottery and tiling, which show they were made for the 20th Roman Legion stationed in Chester in 167 AD.
The prehistoric find confirms archaeologists’ previous suspicions that there may have been signs of activity in the area. In 1993 clues were found by an archaeological team working as part of the A5300 construction, which also discovered the remains of a Roman farm.
The improvement works are expected to be completed by autumn.
The discoveries will be put on display for the public this Friday at 12pm.