Cardinia Shire, an area of 1280 square km, is headquartered at Pakenham, West Gippsland, 57 km east of central Melbourne. It was formed in 1994 by the amalgamation of Pakenham Shire, the eastern half of Cranbourne Shire and a small part of Sherbrooke Shire. The name came from the Cardinia Creek, a stream with headwaters in the north-west of the shire and which forms most of the west boundary of the shire before it enters Western Port Bay east of Tooradin. It is thought that the name derived from an Aboriginal expression about looking towards the rising sun.
The north part of the shire is in the foothills of the Dandenong Ranges, which are a catchment for the Cardinia Reservoir (1973) part of the water supply for Melbourne's south-eastern suburbs and the Mornington Peninsula. The shire's northern slopes also include the Bunyip State Park. Crossing the shire from west to east at about its mid point is the Gippsland rail/highway corridor, with a concentration of populations from Pakenham to Bunyip. Immediately south is the farmland on the former Koo-Wee-Rup swamp, a densely populated rural area with towns at Koo Wee Rup and Lang Lang. On Western Port Bay there are urban settlements from Warneet to Tooradin.
Cardinia Shire's western fringe includes the spread of metropolitan population at Pakenham and Officer. Urban growth has been particularly marked since the late 2000s, with secondary industry and schools being established. Nevertheless, many residents commute to work in Dandenong or metropolitan Melbourne. There are frequent train services to Melbourne and the rural train service stops at stations from Pakenham to Bunyip.
Cardinia Shire's census populations have been:
Cranbourne and Pakenham Shires' entries