Experts suggested the gatherings were like “Glastonbury festival and a motorway building scheme at the same time”, as people spent periods of time each year constructing the site and celebrating massive communal feasts.
The findings overturn the belief that Stonehenge was built as an astronomical calendar or observatory, Professor Mike Parker Pearson from University College London said.
It suggests the act of building monuments was key to those who constructed the site, uniting people from across the island of Britain.
The findings come after a decade of research which included excavations, laboratory work and the analysis of 63 ancient human remains.
The most startling discovery was the scale of the settlement at nearby Durrington Walls, which Prof Parker Pearson described as the “largest Neolithic settlement in the whole of northern Europe”, with about 1,000 houses.
This has led the team, whose findings are being revealed in a Channel 4 documentary, to conclude 4,000 people would have gathered at the site – a huge number given that Britain’s population is estimated to have been only tens of thousands at the time.
By testing cattle and pig teeth found among 80,000 animal bones at Durrington Walls, Prof Parker Pearson and his team discovered people travelled with their livestock from as far away as the Scottish Highlands.
They have also established that there was a peak in killing the animals around nine months after their spring births, which points to the winter solstice being a time of mass feasting.
A smaller peak in the slaughter of the animals occurred around the summer solstice, showing people also celebrated then.
Prof Parker Pearson said he believed that people would have gathered from around the country for a burst of activity to work on constructing the site around the solstices, then dispersed.
Secrets of the Stonehenge Skeletons is being shown on Channel 4 at 8pm on March 10.