In 1914 Canada, as part of the British Empire, went to war against Germany and the Austro-Hungarian Empire. By 1918 the Canadian army had become an independent fighting unit, and in 1919 Canada insisted on signing the Versailles peace treaty on its own behalf. A growing sense of independent nationhood, fostered by battlefield victories and enormous casualties, was one critical consequence of the Great War. War memorials in almost every city, town, and hamlet recorded the devastating local impact of this overseas conflict. Other lasting effects of the war included a larger federal bureaucracy resulting from new social responsibility for veterans and war widows, precedent-setting revenue generation through income and other taxes, and a growing public debt. Female participation in the home-front war effort contributed to federal legislation on women's suffrage during the war.
All regions contributed manpower to the Canadian Expeditionary Force (CEF), which received basic training at some sixty centres across Canada before going overseas. The needs of modern machine warfare created a wartime manufacturing effort, which used the existing expertise and infrastructure in Central Canada and thus reinforced the favoured position of this area. Varying regional contributions to the war effort were also evident in the Victory Loan and Canadian Patriotic Fund campaigns. In 1917 the conscription issue revealed deep divisions within Canada: many French Canadians regarded the struggle in Europe as a British and imperial war rather than a defence of Canada; western Canadian farmers objected to conscription taking away necessary farm labourers; and union leaders argued that 'equality' of sacrifice should involve the conscription of wealth as well as manpower. The War Measures Act, which was enacted during the early enthusiasm for the war, allowed for the disenfranchisement, denial of civil rights, and often internment of 'enemy aliens' and radicals.
In most areas of Canada more than one regiment recruited men, but in St John's in Newfoundland only the Royal Newfoundland Regiment (RNR) was active- As in other places the impact of service was devastating on the local community. Of the 24% of the RNR that came from St John's almost half sustained casualties, many at Beaumont Hamel on 1 July 1916, the first day of the Battle of the Somme. The war killed or injured 15% of the city's men between 18 and 32 years of age.
Most fighting occurred along a 160-km front in France and Belgium. Conflict in eight regions that now have hauntingly familiar names led to a final resting place in this area for some 39 000 of the 61,000 Canadians who died.
Non-combatant Canadian troops also contributed through forestry projects in Scotland and railway building behind the front.
The Military Hospital Commission was established in 1916 to provide convalescent homes for soldiers returning as invalids from overseas and to arrange for their discharge. Where facilities were not available for leasing, the commission erected new hospitals. Because of the rigours of the transatlantic voyage, active treatment (except that required by amputees) was carried out in hospitals in England and France staffed by Canadian Army Medical Corps. In Canada it was administered at municipal or private hospitals that had on-call bed-space or at military-base hospitals. Military hospitals generally served non-battle casualties.
The British government established the Imperial Munitions Board in Canada to bring order to the country's fledgling munitions industry. In addition to co-coordinating contracts for ships, aircraft, chemicals, explosives, weapons, and ammunition at existing factories, the board also established seven new 'national factories' to produce war materiel.