Hertfordshire Police has been contacted for comment.
One resident, who did not want to be named, said officers entered the site at about 09:00 BST.
Protesters clapped and cheered as the first vans and diggers left the site at about 09:30.
East Hertfordshire District Council staff first became aware of the digging, which did not have planning permission, on Saturday morning.
The injunction temporarily blocked further development on the land, bringing caravans on-site, as well as banning anyone occupying the plot.
Residents have said the site was often visited by muntjac deer and had a rich ecosystem.