The South Africa Act 1909 was an Act of the British Parliament which created the Union of South Africa from the British colonies of the Cape of Good Hope, Natal, Orange River Colony, and Transvaal. The Act also made provisions for admitting Rhodesia as a fifth province of the Union in the future, but Rhodesian colonists rejected this option in a referendum held in 1922. The South Africa Act was the third major piece of legislation passed by the Parliament of the United Kingdom 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 (Canada – which became Ontario and Quebec – Nova Scotia, and New Brunswick) and the Commonwealth of Australia Constitution Act, 1900 had united the Australian colonies.