The regiment was redesignated the 4th Battalion, Canadian Mounted Rifles, CEF on 1 January 1916 and was disbanded on 6 November 1920.

[2] Most of their recruits came from the militia cavalry regiments from Militia District 2: The Governor General's Body Guard, the 2nd Dragoons, the 9th Mississauga Horse and the 25th Brant Dragoons.

[3] The battalion had four Officers Commanding: One member of the battalion, Pte Thomas William Holmes, was awarded the Victoria Cross for his actions on 26 October 1917 during the Battle of Passchendaele.

Pte Holmes, then 19, is Canada's youngest Victoria Cross recipient.

The 4th Battalion, Canadian mounted rifles is perpetuated by The Governor General's Horse Guards.