An enforcement notice has been served on the National Trust by a local council because of ongoing problems with travellers and pagans.
The council says the behaviour of some travellers is getting worse
Kennet District Council issued the planning enforcement notice on the trust after overnight problems at Avebury Stone circle in Wiltshire.
A spokesman said complaints had been received about bad behaviour caused by the influx of New Age visitors.
The trust has until 6 November to lodge an appeal.
A council spokesman said: "The council has warned the National Trust that it should not allow overnight camping and caravanning in its car parks because it is a breach of planning control.
"The trust has responded by saying that it is trying to find an alternative site."
Regional director Brendan McCarthy said the trust had been working hard to find a solution that balanced a large number of factors and interest groups.
He said: "We are all aware of the unsuitability of the current car park for the larger pagan celebrations and the trust is committed to finding an alternative which will be acceptable to all parties."