Canadian Mounted Rifles was part of the designation of several mounted infantry units in Canada in the late 19th and early 20th centuries.
Permanent Active Militia was the proper name of Canada's full-time professional land forces from 1855 to 1940, when it was reorganized into the Canadian Army.
It was originally intended that the second Canadian contingent would consist of a CMR unit of three squadrons recruited among the militia located in eastern Canada. This concept provoked disagreement at the highest Canadian political level, as the Governor General believed that more troops should be recruited in western Canada where more individuals had relevant civilian experience. As a political compromise, two units of two sabre squadrons each were formed, despite the lack of tactical sense to such a structure.
The third contingent was recruited at the expense of the British government and consisted of one 901-person unit - 2 CMR - that contained six sabre squadrons.
The fourth contingent consisted of four units, each with four sabre squadrons, that have been described as the only sensibly organized Canadian mounted units in the war, other than the Strathcona's Horse. These units arrived in South Africa after the war had ended.