The Corporate Town of Peterborough was established by separation from Yongala in 1886.

Local government in the rest of the county was established in 1888 by the creation of the District Council of Orroroo at Orroroo and the District Council of Carrieton at Carrieton.

They were created by the passage of the District Councils Act 1887 on 5 January 1888.

As part of the same legislation in action, the District Council of Caltowie gained the Hundred of Tarcowie in the south west corner of the county.

The Orroroo and Carrieton councils also amalgamated in 1997 to form the District Council of Orroroo Carrieton, which is currently the main local government body in the county.