The Government of Queensland created the City of Brisbane with a view to uniting the then Brisbane metropolitan area under a single planning and governance structure. The City of Brisbane Act 1924 received assent from the Governor on 30 October 1924. On 1 October 1925, 20 local government areas of various sizes were abolished and merged into the new city.
The City of Brisbane is governed by the Brisbane City Council, the largest local council in Australia. The Brisbane City Council has its power divided between a Lord Mayor, a parliamentary-style council of twenty-six councillors representing single-member wards of approximately 23,000 voters (roughly equivalent in size to state electorates), and a Civic Cabinet comprising the Lord Mayor, the Deputy Mayor (drawn from the majority on Council) and the chairpersons of the seven standing committees drawn from the membership of Council. Due to the City of Brisbane’s status as the country’s largest LGA, the Lord Mayor is elected by the largest single-member electorate in Australia. Like all mayors in Queensland, he has very broad executive power.
History info thanks to Wikipedia