Northamptonshire County Council plans to sell the historic County Hall building in Northampton town centre.
The sale of the listed building will help reduce annual rent costs for the authority, which also aims to generate extra income by sub-letting parts of One Angel Square.
Since council staff relocated to Angel Square last May, the County Hall site in George Row has become underused, the authority says.
The council chamber, coroner’s courts and tourist information centre are based in the George Row building and if the sale of the site goes ahead, these services would be relocated.
The proposals will be discussed at a cabinet meeting next Tuesday (June 12).
County council cabinet member for finance Cllr Michael Clarke said: “Our move from 12 expensive buildings in Northampton into One Angel Square last year is already proving cost-effective and enabling us to adopt more modern ways of working.
"The proposed accommodation strategy will allow us to make even better use of our new headquarters.
“The building was carefully designed to enable flexible ways of working and by reconfiguring the layout, we can maximise the space available to bring partner organisations into One Angel Square, achieving closer collaboration with partners and delivering additional income for the council.
“At the same time, we are looking to dispose of the County Hall site which was once our democratic hub and is now hugely under-utilised.
"The imminent transformation of local government in Northamptonshire offers us an opportunity to review the use of the site and look at alternative venues for full council meetings.”
If County Hall is sold there would be a staged withdrawal from the site, which the council aims to complete by the time unitary authorities are in place in Northamptonshire.
According to a council report, the estimated yearly cost of running County Hall - without accounting for staff costs - is £380,000.
The same report notes there is a range of artworks currently inside County Hall, which it says will need to be professionally assessed before its future is decided.
The county council sold One Angel Square last month to Canada Life Investments on a 35-year leaseback arrangement.
Estimates suggest the space made available for third-party occupation in One Angel Square would generate about £500,000 per year for the authority.
The oldest parts of County Hall date back to the mid-1700s. The front block, the judge's lodgings and the centre block of the building are Grade II listed, while Sessions House is Grade I listed.