On 1 January 1901, the colonies of Australia federated to form the Commonwealth of Australia. When Chauvel returned to Australia on 17 January, he found that during his absence he had become an officer in the newly formed Australian Army. A force of 14,000 troops was assembled for the opening of the first Federal Parliament on 9 May 1901 in Melbourne; Chauvel was selected as brigade major of the mounted contingent, his first Federal posting. He became Staff Officer, Northern Military District, based at Townsville, Queensland, in July. In 1902, Chauvel was appointed to command of the 7th Commonwealth Light Horse, a unit newly raised for service in South Africa, with the local rank of lieutenant colonel. Departing from Brisbane on 17 May 1902, the 7th Commonwealth Light Horse arrived at Durban on 22 June, three weeks after the war ended. It therefore re-embarked for Brisbane, where it was disbanded. Chauvel remained in South Africa for a few weeks in order to tour the battlefields. On returning to Australia he became Staff Officer, Northern Military District once more. He was promoted to the brevet rank of lieutenant colonel in December 1902.