Is Sydney really Australia’s largest city?

According to the official population projections from the Australian Bureau of Statistics (ABS), Sydney’s population was 180,300 larger than Melbourne’s in 2024-25:

Sydney is currently Australia’s biggest city because the official boundaries used to draw the city limits are arbitrary.

The official definition of Greater Sydney stretches all the way to Lake Macquarie, about 120 kilometres north of the CBD. As a result, Sydney’s population is bolstered by the inclusion of the heavily populated NSW Central Coast, which ranks as Australia’s 9th largest “significant urban area” in its own right, according to the ABS.