The Local Government Act 2018 has been signed into law by President Michael D Higgins.
This means that the long awaited boundary extension for Cork city will come into force on 4 June following the local elections in May.
The extension, which will see the city footprint increase four-fold, was welcomed by both local authorities.
Earlier today, Mayor of Cork County Councillor Patrick Gerard Murphy said the boundary alteration process had proven very challenging and complex but a line has finally been drawn in the sand and now allows both councils to get on with the transition of some 400 services.
He said he was pleased that the final legislation took account of concerns raised by county councillors.