The shire, administered from the town of Mirani, covered an area of 3,280.2 square kilometres (1,266.5 sq mi), and existed as a local government entity from 1916 until 2008, when it amalgamated with the City of Mackay and the Shire of Sarina to form the Mackay Region.

The shire was situated in the Pioneer Valley, and atop the Eungella Range, to the west of Mackay.

Pioneer Division was one of the 74 divisional boards established on 11 November 1879 under the Divisional Boards Act 1879 with a population of 2884 and covered the region surrounding but not including the Borough of Mackay.

On 15 March 2008, under the Local Government (Reform Implementation) Act 2007 passed by the Parliament of Queensland on 10 August 2007, the Shire of Mirani merged with the City of Mackay and Shire of Sarina to form the Mackay Region.

The Shire of Mirani included the following settlements: Towns: Localities: