Sydney is the capital city of the state of New South Wales and the most populous city in Australia. Located on Australia’s east coast, the metropolis surrounds Sydney Harbour and extends about 80 km (50 mi) from the Pacific Ocean in the east to the Blue Mountains in the west, and about 80 km (50 mi) from the Ku-ring-gai Chase National Park and the Hawkesbury River in the north and north-west, to the Royal National Park and Macarthur in the south and south-west. Greater Sydney consists of 658 suburbs, spread across 33 local government areas. Residents of the city are colloquially known as “Sydneysiders”. The estimated population in June 2023 was 5,450,496, which is about 66% of the state’s population. The city’s nicknames include the “Emerald City” and the “Harbour City”.

The population of Sydney in 1788 was less than 1,000. With convict transportation it almost tripled in ten years to 2,953. For each decade since 1961 the population has increased by more than 250,000. The 2021 census recorded the population of Greater Sydney as 5,231,150. The Australian Bureau of Statistics (ABS) projects the population will grow to between 8 and 8.9 million by 2061, but that Melbourne will replace Sydney as Australia’s most populous city by 2030. The four most densely populated suburbs in Australia are located in Sydney with each having more than 13,000 residents per square kilometre (33,700 residents per square mile). Between 1971 and 2018, Sydney experienced a net loss of 716,832 people to the rest of Australia, but its population grew due to overseas arrivals and a healthy birth rate.