Travellers' "unauthorised encampment" at Newham on edge of Truro
More than 50 travellers have set up camp on the outskirts of Truro.
Police confirmed there are now between 20-30 vans and cars on a public highway at the far end of Newham.
Cornwall Council said there was an "unauthorised encampment" at the site.
Both Cornwall Council and the police will now monitor the situation before any action is taken.