When did western Australia become a part of Australia?

Western Australia has always been part of the continent of Australia. However, the colony of the Swan River in Western Australia was claimed as territory of Australia, rather than remaining as New Holland, in 1829.

In 1829, Captain Charles Fremantle was sent to take formal possession of the remainder of New Holland which had not already been claimed for Britain under the territory of New South Wales. On 2 May 1829, Captain Fremantle raised the Union Jack on the south head of the Swan River, thus claiming the territory for Britain. The Swan River Colony was officially renamed to Western Australia in 1832.