The partners are seeking planning for up to 3,500 new homes within three villages.
The plans include a local centre and two smaller neighbourhood centres, three primary schools and one secondary school, all within 130 hectares of formal and informal open space.
The wider Chelmsford Garden Community also encompasses two developments already under construction, including Beaulieu and Channels, the new community will collectively deliver around 10,000 homes.
Alongside the new Beaulieu Train Station and Chelmsford North East Bypass being delivered by 2026, Chelmsford Garden Community will create a sustainable extension for Chelmsford.
Work on the proposed scheme is anticipated to start in 2025 and would be developed over a 15-year build period.
Martin Leach, managing director of Strategic Land and Major Projects at Countryside, said: “This major mixed-used development will deliver much-needed homes and community facilities, including those outlined in the recent planning application submission, which will significantly improve the lifestyle offering and access to key amenities for the wider Chelmsford community.”