The annual Elland charity bonfire is under threat after travellers moved on to the display site at Hullen Edge Park yesterday.
It is hoped that the site will be cleared before preparation for the event needs to get underway.
The bonfire and firework display is planned for next Saturday - November 1 - and has taken months of planning.
Malcolm Coton, of Elland Round Table, said: “Four to five thousand people are expected next weekend and preparations need to start from Monday.
“We have pallets, toilets, cabins and rides being delivered next week and we’re hoping that they will realise its a community event and move off the site.
“If the event was jeopardised there would be a big impact as all the money raised goes back into the community.”
The annual event raises around £12,000 per year for charities across the district.