[1][2][3][4] With the passing of the Militia Act of 1855, the first of a number of newly-raised independent militia companies were established in and around the Grey County region of Canada West (now the Province of Ontario).
[1][2] During the South African War, the 31st Grey Battalion contributed volunteers for the Canadian Contingents serving overseas.
[1] During the First World War, the 31st Grey Regiment as a unit was not mobilized but when the Canadian Expeditionary Force was raised in September 1914, drafts from various units were called up and formed into numbered battalions.
[2] On 1 May 1920, as a result of the Otter Commission and the following post-war reorganization of the militia, the 31st Grey Regiment was Redesignated as The Grey Regiment and was reorganized with two battalions (one of them a paper-only reserve battalion) to perpetuate the assigned war-raised battalions of the Canadian Expeditionary Force.
[2][7] As a result of the 1936 Canadian Militia reorganization, on 15 December 1936, The Grey Regiment was amalgamated with The Simcoe Foresters to form The Grey and Simcoe Foresters.