The housebuilder has submitted planning applications for the next phase of the 1,800-home mixed-use North Leigh Park project, predicting a £250m construction investment over the 10-year build programme.
Advised by planner Lichfields, Countryside has put in plans for 507 homes, a new link road and a local centre to Wigan Council.
A reserved matters application includes details of 257 units in a mix of 50 two-bed, 195 three-bed and 12 four-bed family houses.
Out of these, 161 would be delivered as affordable housing, made up of both shared ownership and affordable rent options.
A second hybrid application, including both outline and detailed proposals, has been submitted for 250 homes and a link road, from Leigh Road to Atherleigh Way.
The development would be a mix of 44 two-bed, 165 three-bed, and 41 four-bed family homes, including 59 affordable homes.
This application also seeks outline consent for a local centre which could include shops, cafés, restaurants and health uses, to the north of the link road.
Lichfields said it estimates the total construction cost of the development will be £250m, and the scheme is expected to create 426 full-time construction jobs over the 10-year build programme.
Outline approval was granted for the North Leigh Park development in 2013.
The site to the south east of Wigan is made up of mostly vacant land and is bordered by two main roads, the A577 to the north and A578 to the west with Westleigh High School to the south east of the site.
Countryside acquired the site in a process run by CBRE in 2018. The site had been promoted by North Leigh Park Group, part of Guernsey-based Long Port Properties, but Long Port put the business into administration in December 2016.
Last year Lichfields secured approval for the first phase made up of 199 homes.