Mackay Regional Council was established in 2008 by the amalgamation of Mackay City, Mirani Shire and Sarina Shire.

The history of local government in the Mackay region is:

Municipality of Mackay established, south from Pioneer River to Racecourse, east from the Lagoons.1869
Pioneer Divisional Board established, south from O'Connell River (near Midge Point) to Cape Palmerston, inland to Cattle Creek.1880
Pioneer Shire declared.1903
Sarina Shire established, south from Dalrymple Bay to Cape Palmerston, by severance from Pioneer Shire.1912
Mirani Shire established, inland from Marian to Eungella, by severance from Pioneer Shire.1913
Mackay declared a City.1918
Mackay City and Pioneer Shire amalgamated.1994
Mackay City, Mirani Shire and Sarina Shire amalgamated.2008

The amalgamation in 2008 had the following statistics:

MunicipalityArea
(sq km)
Population
(2006 census)
Mackay289984,856
Mirani32805558
Sarina144410,360
Combined7621100,260

Mackay City, with its large hinterland, extended coastwise from the Laguna Quays resort to the Sandringham Bay inlet. Sarina Shire lay to its south. West of Mackay City the Shire of Mirani occupied much of the unsettled or barely settled ranges. Its settlement was concentrated along the valleys of the Pioneer River and Cattle Creek, as far west as the Eungella National Park. The railway network reached nearly to Eungella by 1911, but it now ends at Marian (see Mirani Shire entry for details of the cane railways).

Mackay was connected to the North Coast line by the 1920s, and a short line was built to the Mackay Harbour in 1938. As the cane lines were closed in the 1970s, a railway was built from the south-western coalfields to a large export terminal at Hay Point (1971). Sarina Shire's coastal towns became dormitory sites for coal-export workforces, as well as attracting residents and retirees. 

During the 1990s-2000s Sarina Shire had steady population growth, particularly in the coastal townships. Mirani Shire's population fell slightly during the 1990s. Each shire had two things in common: significant sugar-cane growing and processing, and visitation to Mackay as a regional centre. It was estimated that 25% of Sarina Shire's employed people worked in Mackay.

The Mackay Regional Council's census populations have been:

census datepopulation
2011112,798
Further Reading: 

Mackay, Mirani Shire, Pioneer Shire and Sarina Shire entries