Victoria is the second most populous state in Australia. Geographically the smallest mainland state, Victoria is bordered by New South Wales to the north, South Australia to the west, and Tasmania to the south, across Bass Strait. Victoria is the most densely populated state, and has a highly centralised population, with almost 75% of Victorians living in Melbourne, the state capital and largest city. Approximately 30,000 Indigenous Australians are estimated to have lived in the area, before European settlement in Victoria began in the 1830s. The discovery of gold in 1851 at Ballarat and Warrandyte transformed it into a leading industrial and commercial centre.