An historic county council headquarters which has been derelict for 14 years could be converted into new flats.
Suffolk County Council moved out of the Grade-II listed building on St Helen's Street, Ipswich, in 2004.
It has attracted unsuccessful proposals since, including a new registry office, homes and an archive centre.
Thurlow Architects said the flats would retain the building's "iconic" features, according to the Local Democracy Reporting Service.
The main structure dates back to 1906, although some parts date back to 1837, and one small section to 1786.
It has previously been used as law courts and a jail, and has been heavily vandalised since the council moved to Endeavour House in Russell Road.
Under the plans, County Hall itself would become 12 flats and a new accommodation block would be built behind, comprising two maisonettes and a further 28 flats.
Carole Jones, councillor for planning and development at Ipswich Borough Council, said: "The old County Hall is one of our most important buildings and it is vital that it comes back into use."
A spokesman from Thurlow Architects was unavailable for comment.
The plans are currently open to public consultation and are expected to go before the council's planning committee in late January or February.