Nearly 3,500 inmates could be housed at two new prisons near Finchingfield and Wethersfield.
The government says it plans to build two prisons holding around 1,715 inmates each on the former RAF Wethersfield base in Essex.
The Ministry of Justice (MoJ) plans to build a new Category B training prison to give long-term of high-security inmates skills, and a Category C resettlement prison for inmates nearing the end of their sentences.
They are part of a £4 billion scheme to create 18,000 extra prison places by the mid-2020
The prisons would sit near the Ministry of Defence Police headquarters at Wethersfield.
The government's new prisons minister Victoria Atkins MP said: "Prisoner numbers change over time which is why we must have robust plans in place to make sure we will always have enough places available.
"We expect there will be an increase in demand for prison places as the activity of our courts system continues to ramp up to full operating capacity following the national restrictions due to the Covid-19 pandemic."
According to Ministry of Justice statistics, the crown court had a backlog of 59,532 unresolved cases in the first quarter of 2021 (January-March).
The UK's prison population stood at 78,830 on Friday, September 24.
The number of inmates at Chelmsford's Category B unit will be temporarily cut by 55 to 695 after safety experts revealed this month that conditions in the prison had "declined disturbingly" in recent years.
Mrs Atkins added: "We believe that, following detailed feasibility work, land at RAF Wethersfield would be an appropriate location for two new prisons.
"Our plans, if successful, would bring many benefits to the local community, such as hundreds of jobs during construction, careers within the prison sector and an increased spend in local businesses."
An MoJ document notes that the prison could create 1,200-1,400 permanent jobs.
The design for the units has not been finalised, but each prison will feature seven four-storey 'house blocks' to create a sense of community and reduce violence.
It will also feature daytime accommodation for prison dogs and polytunnels for gardening.
A consultation on the plans is online: https://consult.justice.gov.uk/digital-communications/proposed-new-prisons-in-wethersfield-consultation/
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