Four new councils covering larger areas will be created on the mainland, with the Isle of Wight remaining a standalone local authority.
Southampton, Eastleigh, the Waterside area of the New Forest and southern parts of Test Valley will form one council.
Portsmouth will be paired up with Fareham, Havant, Gosport, southern parts of East Hampshire and one parish of Winchester.
The rest of the New Forest will become part of a council with the remaining Test Valley, East Hampshire and Winchester areas.
The north of the county will see Basingstoke and Deane combined with Hart and Rushmoor.
Hampshire County Council leader Nick Adams-King revealed the details, with the government set to be announcing its decision this afternoon.
It comes after months of uncertainty and rows over the best approach.
Four different merger options were put forward by the region’s existing local authorities.
The option favoured by ministers was the preference of local authorities in Eastleigh, Fareham, Hart, Havant, Portsmouth and Southampton.
The only subject with unanimous backing was for the Isle of Wight staying a separate council.
New Forest District Council was strongly opposed to seeing its area split up across two new councils.
The majority of councils continued to work collaboratively throughout the process, setting out the case for four local authorities on the mainland with three different configurations.
Hampshire County Council and East Hampshire District Council focused on building their own case for a three-authority model.
Gosport Borough Council refused to engage with the process and did not respond to the government’s consultation on a preferred option.
The new unitary authorities are set to take over services from April 2028.
Elections for shadow authorities, which will prepare for the implementation date, will be held in May next year.
The mergers, known as local government reorganisation, are being brought forward as part of the Labour government’s move to end the two-tier structure.
At present, Hampshire has a mix of areas with district or borough councils delivering some services alongside the county council providing others, and unitary authorities delivering all services in Portsmouth, Southampton and on the Isle of Wight.
The local government reorganisation of Hampshire will create four unitary councils on the mainland in the following configuration.
South West Hampshire: Eastleigh, Southampton, New Forest areas of Totton and Eling, Marchwood, Hythe and Dibden, and Fawley, and Test Valley areas of Valley Park, Chilworth, and Nursling and Rownhams.
South East Hampshire: Fareham, Gosport, Havant, Portsmouth, East Hampshire areas of Clanfield, Horndean and Rowlands Castle, and Winchester area of Newlands.
Mid Hampshire: Remaining areas of New Forest, Test Valley, Winchester and East Hampshire.
North Hampshire: Basingstoke and Deane, Hart and Rushmoor.