Campaigners have given planners 6,000 reasons not to build 3,500 new homes on meadows near Burgess Hill.
West Sussex County Council's planning department has been swamped with protests against the proposals drawn up by the West Burgess Hill Company.
Opponents of the development believe it will cause traffic gridlock and flooding chaos in the town and surrounding villages.
The county council has received 1,072 letters of protest detailing more than 6,000 points of opposition.
Almost a quarter of the 4,505 responses to West Sussex's draft county structure plan were devoted to West Burgess Hill.
The plan is about to be reviewed by a government-appointed inspector.
The West Burgess Hill Company wants to build 3,500 homes and 500,000 square metres of business space on the 460-acre stretch of farmland to the west of Burgess Hill, promising to invest in roads and schools.
Director Martin Wilkes has said the development could create up to 5,000 skilled jobs in areas such as computing and information technology.
But the scheme has been labelled "madness" by opponents including Mid Sussex District Council, Burgess Hill Town Council and Haywards Heath Town Council.
Opponents fear the scheme would overwhelm not only Burgess Hill but neighbouring towns and villages.
Residents south of the A272 fear they will be at increased risk of flooding and some say the housing scheme would be better at East Grinstead.
Maxine Tyler, chair of the Hurstpierpoint Society, said the village was unanimous in opposing the housing proposals.
She said: "Burgess Hill has already grown more than enough over the last 15 years. It doesn't have the infrastructure to cope.
"There is a phenomenal amount of opposition, as these letters show. The momentum has grown as more people have realised the disastrous implications this development would have. I just hope West Sussex County Council listens."
Carole Preston, Haywards Heath town clerk, said: "More people would be travelling to our station to commute to London and would clog up the whole area.
"But if you read between the lines, it seems even if West Sussex listens to our wishes the Government will ride roughshod over our protests because it wants more homes."
Christopher Maidment, a leading campaigner against the plans, said another battle was against public cynicism that the development was inevitable.
He said: "In the months of my personal involvement in this campaign to prevent West Burgess Hill, nothing has aggravated me more than those who say it's a done deal, and that 'money talks'.
"This is far from a done deal. There's a great deal of disquiet at County Hall, and rightly so"
The structure plan will be submitted to a public examination in December.
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