Suffolk Coastal and Waveney DCs have approved plans to formally merge and create a new ‘super district' council.
If approved by the Department for Communities and Local Government, it will be the first time two districts have merged since local government reorganisation in 1974.
Suffolk Coastal leader, Cllr Ray Herring, said: ‘By creating a new, larger and more influential council, we will be able to keep costs down, enabling us to maintain and improve the services that local people depend on.'
The two councils have been sharing a chief executive since 2008 and working in partnership has already helped them save more than £16m since 2010.
Cllr Herring continued: ‘Further savings cannot be made unless the partnership progresses further.
‘A new, merged, council will be better placed to address the shared challenges that both councils face.'
Elections to the new authority are expected to take place in May 2019.