Some 400 people are set to be made homeless on 31 August.
Travellers at the Dale Farm site in Basildon, Essex, were issued eviction notices by the council two weeks ago.
They say that everyone has to leave by 31 August—or they will be forcibly removed.
Dale Farm is one of the biggest Traveller sites in Britain and people have lived there since the 1970s.
They own the land.
Travellers and their supporters are organising now to physically defend the Dale Farm site.
To get involved with the campaign go to http://dalefarm.wordpress.com