The South Africa Act 1909 was an Act of the Parliament of the United Kingdom, which created the Union of South Africa from the British Cape Colony, Colony of Natal, Orange River Colony, and Transvaal Colony. The Act also made provisions for potentially admitting Rhodesia as a fifth province of the Union, but Rhodesian colonists rejected this option in a referendum held in 1922. The Act was the third major piece of legislation passed by the British Parliament with the intent of uniting various British colonies and granting them some degree of autonomy. Earlier, the British North America Act, 1867 had united three colonies (the Province of Canada (which was split into Ontario and Quebec) Nova Scotia, and New Brunswick) and the Commonwealth of Australia Constitution Act, 1900 had united the A