What is an electoral division or electorate?

An electoral division (or electorate) is the geographic area represented by a single Member of the House of Representatives in the federal Parliament. Australia is divided into 151 federal electorates, each of roughly equal population, with each returning one member to the House at every federal election or by-election. Electorates are sometimes also called seats.

Each state's number of electorates is calculated using a quota system set out in section 24 of the Constitution. The Australian Statistician calculates each state's entitlement after each Census and at the start of each Parliament. New South Wales currently has 47 seats, Victoria 39, Queensland 30, Western Australia 16, South Australia 10, and Tasmania 5 (the constitutional minimum for an original state). The Australian Capital Territory has three seats and the Northern Territory has two seats.

Electorate boundaries are reviewed regularly by the Australian Electoral Commission's redistribution committees. Each state and territory is redistributed every seven years, or when its entitlement to seats changes, or when more than one-third of electorates within the jurisdiction have moved more than 10 per cent away from the average enrolment. The redistribution process is independent of government, with public submissions and objections invited at multiple stages. Boundaries are drawn to produce roughly equal numbers of voters per electorate within each state.

Electorate names usually honour Australian people or places. Many are named after former Prime Ministers, explorers, scientists, or political figures (Barton, Curtin, Menzies, Higgins, Florey, Bonner, Lalor, Mackellar). Many are named after geographic features (Sydney, Hunter, Brisbane, Perth, Canning). Some honour Aboriginal and Torres Strait Islander figures (Indi after the Indigenous name for the Murray River, Lingiari after Vincent Lingiari of the Gurindji people, Bennelong after the Eora man who lived with the colonists). Boundary changes can produce significant political effects, with newly drawn marginal seats often becoming the focus of intensive campaigning.