Residents in Berkshire have begun a campaign to fight plans to build nearly 3,500 new homes in their village.
There are currently about 5,500 homes in Crowthorne.
Plans proposed by both Wokingham Borough and Bracknell Forest Councils could see that nearly double, with 60% more homes built.
Carole Doran from Crowthorne Village Action Group (Cvag) said the plans were "horrendous" and would change the character of the village forever.
Crowthorne sits on the border between the two borough councils.
Bracknell, which wants 1,600 new homes, and Wokingham, which has plans for 1,850 homes, both said they would consult and work together on proposals for new build.
Ms Doran said: "We're not opposed to development but it has to happen at a pace that the infrastructure can cope with and it has to be acceptable.
"What's being proposed is absolutely horrendous and would change the character of our village completely.
"It would join us physically to Wokingham and to Bracknell - it would become part of an urban sprawl which is totally unacceptable."
Angus Ross, executive member for planning at Wokingham Borough Council, said: "I totally understand the concerns of the residents.
"But the 1,850 homes around the south part of Wokingham that the borough council's already agreed in January would go in are more than a mile away from any other buildings in Crowthorne.
"Yes, there's an awful lot of houses going in but there is still good separation and that will be very protected."
Bev Hindle, chief officer planning and transport at Bracknell Forest Council, said the authority would "continue to seek views on potential development areas for new neighbourhoods".