Protected landscape will be damaged and villages will be blighted by lorries, campaigners against a rail and road freight interchange depot have claimed.
The planned depot would transfer freight from the road onto trains
Protesters want the Kent International Gateway proposal for land west of junction eight of the M20 near Bearsted to be rejected by the council.
Consultation has begun on the plans for warehouses, offices, roads and bridges on a 112.3-hectare site (270 acres).
Developers said the railways would take on substantial road freight movements.
The creation of about 3,500 jobs has also been promised if Kent International Gateway gets planning approval.
Maidstone Borough Council said a three-week consultation period on the application would involve letters to residents, site notices and meetings with councillors and interested groups.
A decision is not expected until February at the earliest.
The council said the proposal was for a "rail/road freight interchange incorporating buildings for warehousing, distribution and offices, research and development, and light industrial units".
The Stop KIG group has set up a campaign website, with protest T-shirts and posters on offer.
Spokeswoman Val Springett said: "It's in the wrong place and it's a very ill conceived idea.
"At the moment the land is protected... I think most of the people who have seen the site plan didn't realise how huge this proposal is."
Kent International Gateway spokesman Steve Messenger argued changes had already been made to the plans following a public exhibition, and said the developers were "doing all we can to minimise the impact of the proposals on residents living in the immediate vicinity".
The KIG depot would operate up to 13 freight trains a day, removing an estimated 60 million kilometres (37.3 million miles) of HGV movements from the roads each year.
One-third of the total site area would be given over to landscaping, woodland retention and new wildlife habitats.