Grey belt sites across England could potentially deliver 3.4 million new homes, according to data from Searchland.
The data shows there are around 30,597 grey belt sites, with the North West region having the highest number at 5,858, which could accommodate 720,592 new homes.
The South East has 18% of the total grey belt sites, the East of England has 16%, while both West Midlands and Yorkshire and the Humber each have 15%.
Kirklees has the most grey belt sites at 1,005, able to provide 104,487 new homes.
Cheshire West and Chester has 914 sites, capable of delivering 96,126 new homes, while Tandridge has 779 sites that could house 51,734 properties.
Other notable areas in the top ten include Cheshire East (741), Leeds (687), Bradford (672), Wakefield (670), Buckinghamshire (623), Bromsgrove (596), and Calderdale (569).
Hugh Gibbs, co-founder of Searchland, said: “Building on the Green Belt has been a hot topic for many years, and while those campaigning against concreting over the countryside are right to do so, there are swathes of land that don’t look like the beautiful rolling countryside you’d imagine.
“So it’s great to see that our new Labour government has decided to act with a degree of common sense by bringing in the grey belt classification and identifying the areas of wrongly classified Green Belt that are ripe for development.
“As our data shows, this could help boost the level of new homes reaching the market by 3.4m properties, which is more than double Labour’s ambitious target of 1.5m homes by 2030.”