New South Wales (abbreviated as NSW) is Australia's oldest and most populous state, located in the south-east of the country, north of Victoria and south of Queensland. It was founded in 1788 and originally comprised much of the Australian mainland, as well as Lord Howe Island and Norfolk Island. Some early governors considered it also included New Zealand until British officials pointed out this was not so. Nevertheless when Britain annexed New Zealand in 1840 it was briefly a part of New South Wales. During the 19th century large areas were successively separated to form the British colonies of Tasmania, South Australia, Victoria, Queensland and New Zealand. It is named after the British region of South Wales.

Inhabitants of New South Wales are referred to as being New South Welsh or New South Welshmen. New South Wales' largest city and capital is Sydney.