The South African Mounted Rifles were formed on 1 April 1913 from existing provincial Permanent and Police forces. The 1st Regiment was formed from the Cape Mounted Rifles, the 2nd from the Natal and Free State Police, the 3rd from the Natal Police, the 4th from the Transvaal Police and the 5th from the Cape Mounted Police. Until the start of WW1, the SAMR did policing work in many areas of South Africa.
When WW1 started, the SAMR became the 6th Mounted Brigade. They served in German South West Africa and then returned to South Africa where many memebers were released to serve in the Overseas Expeditionary Forces. The remainder did policing duties in South Africa.
In 1920, the disbandment of the force began. Most members then joined the newly formed South African Police. In 1926, the last regiment was disbanded.