At the outbreak of war, the 34th Ontario Regiment was asked to supply 125 men from Ontario County for the First Contingent of the Canadian Expeditionary Force. In addition to the first 18 volunteers from Whitby, the 34th Ontario Regiment called up seven officers and 200 other ranks to join the training operations in Valcartier, Quebec.

The 34th Ontario Regiment continued recruiting men and women for service overseas when in October 1915, the 116th Ontario County Battalion was authorized and established at Uxbridge. The Battalion's C Company was based out of Whitby with Major George W.P. Every as commanding officer.

During training, the 116th Battalion marched from Beaverton to Whitby prior to participating in a mock battle and military review which took place at the southwest corner of Dundas and Annes Streets on May 26, 1916. The day was declared a public holiday so that Whitby citizens could watch the events.

Six months following its initial authorization, the 116th recruited 1145 men and the battalion set sail for Europe in July 1916. Throughout the war, the 116th Battalion stayed together and participated in many battles including, Vimy, Ypres, and Passchendaele. The 116th Battalion was disbanded in August 1920 but is perpetuated by the 34th Ontario Regiment Royal Canadian Armoured Corps.