| 1636-1640 | Epidemic | | The first recorded epidemic of smallpox in Canada occurs when Jesuit priests attending to the sick unintentionally spread the disease | Ontario |
| 1659 | Epidemic | | Typhus first appears in Canada | Ontario |
| 1732-1733 | Epidemic | | Influenza epidemic | Ontario |
| 1755-1757 | Epidemic | | Smallpox epidemic in the Niagara area, as well as in Quebec and New England | Niagara area |
| 1759 | Epidemic | | Measles epidemic | Ontario |
| 1761 | Epidemic | | Influenza epidemic | Ontario |
| 1772 | Epidemic | | Measles epidemic | Ontario |
| 1775-1776 | Epidemic | | Influenza epidemic | Ontario |
| 1780 | Epidemic | | Smallpox epidemic hits the Hudson Bay area | Hudson Bay |
| 1788 | Natural Disaster | | Famine hits Upper Canada when crops fail | Upper Canada |
| 1804 | Accident | 20-50 | Aug 10: On the way to Presqu'ile Point, the Schooner 'Speedy' sank in Lake Ontario. Everyone aboard drowned, including some of Upper Canada's leading citizens (learn more) | Lake Ontario |
| 1812-1815 | War | ~8600 | The War of 1812 claims an estimated 8,600 British and Canadian soldiers and civilians either due to battle or disease. | Ontario |
| 1819 | Natural Disaster | | Summer: A fire devastates part of the counties of Lincoln & Welland | Lincoln & Welland Counties |
| 1832 | Epidemic | 600 | Cholera spreads from Quebec killing almost 600 in Ontario, and a total of 6,000 Canadians across the country | Ontario |
| 1834 | Epidemic | | Province-wide cholera epidemic that lasted approximately 4 months during the summer and early fall | Ontario |
| 1838 | Epidemic | | An epidemic of Ague depleted the population of Lindsay by one-third | Victoria County |
| 1847-1848 | Epidemic | | Influenza epidemic | Ontario |
| 1847-1849 | Epidemic | | Typhus and Cholera come ashore during the 'black year of emigration' when more than 5,000 Irish immigrants arrive in Cobourg and other lake ports | Ontario |
| 1850-1851 | Epidemic | | Influenza epidemic | Ontario |
| 1853 | Accident | ~50 | Apr 30: The steamer 'Ocean Wave' burned and sank in Lake Ontario (additional details are available in the CanadaGenWeb Archives) | Lake Ontario |
| 1854 | Accident | 52 | Oct 27: The worst rail disaster of its time occurred near Jeannettes Creek when two trains collided killing 52 (learn more) | Jeannettes Creek, Kent County |
| 1857 | Accident | 66 | Mar 17: A bridge over the Des Jardines Canal collapses while a train is crossing, killing 66 people (learn more) | Burlington Heights, Halton County |
| 1857-1859 | Epidemic | | Influenza epidemic | Ontario |
| 1866 | War | 31 | Fenian Raids claim 31 lives (learn more) | Niagara area |
| 1871 | Epidemic | | Jan-Jun: Scarlet fever claims a large number of Renfrew County inhabitants | Renfrew County |
| 1873-1875 | Epidemic | | Influenza epidemic | Ontario |
| 1881 | Accident | nearly 200 | May 24: The upper deck of steamboat 'Princess Louise' collapses and nearly 200 are killed or drown (learn more) | London, Middlesex County |
| 1884 | Accident | 30 | Jan 2: Two trains collide in Parkdale killing 30 (learn more) | Parkdale, York County |
| 1884 | Epidemic | | Smallpox epidemic in Hastings County | Ontario |
| 1889 | Accident | 19 | Apr 28: A Grand Trunk railway train jumps the track, killing 19 | Hamilton, Wentworth County |
| 1898 | Accident | 20 | Jan 3: Several hundred people had gathered at London's City Hall to celebrate the election of their new mayor John Wilson when the floor collapsed causing 250 people to fall to the floor below. 20 people died. | London, Middlesex County |
| 1899-1902 | War | 135 | South African War, also referred to as the Second Boer War, claims 135 Canadian lives. | South Africa |
| 1902 | Epidemic | | Smallpox epidemic in Galt | Galt, Waterloo County |
| 1904 | Natural Disaster | 1 | Apr 19: A fire destroys a large section of downtown Toronto learn more) | Toronto, York County |
| 1906 | Epidemic | 70 | Jan-Apr: 70 people in Thunder Bay succumb to Typhoid Fever | Thunder Bay District |
| 1907 | Accident | 8 | Jul 16: Crystal Hall, a three storey building in London, collapses during renovations. Eight are killed. | London, Middlesex County |
| 1907 | Accident | 2 | Aug 10: A train boxcar filled with 5,000 pounds of nitro-glycerine explodes in Essex (learn more) | Essex, Essex County |
| 1910 | Accident | 44 | Jan 21: A CPR passenger train derailed as it crossed the Spanish River near Sudbury. 44 were killed. (learn more) | Spanish River, Sudbury District |
| 1910 | Accident | 11 | May 8: A plant owned by the General Explosives Company explodes killing 11 | Hull, Carleton County |
| 1911 | Natural Disaster | 70 | Jul 11: A hot dry summer sparks several small bush fires that combine to form a large fire spanning over 36km wide. The fire destroys several communities and kills at least 70 people (learn more) | Porcupine, Cochrane District |
| 1913 | Natural Disaster | 250+ | Nov 7-10: A blizzard with hurricane-force winds, later known as the Great Lakes Storm of 1913, hit four of the five Great Lakes destroying 19 ships and killing more than 250 people. (learn more) | Great Lakes |
| 1914-1918 | War | 68,000+ | World War One claims more than 68,000 Canadians | Europe |
| 1915 | Accident | 15 | Jul 7: Due to heavy rains, a streetcar in Queenston Heights rolled down the escarpment killing 15. All were members of two Toronto churchs on their way to a picnic. | Queenston Heights, York County |
| 1916 | Natural Disaster | 223 | Jul 29: A forest fire now known as the 'Matheson Fire' destroys several towns, killing an estimated 223 people (learn more) | Cochrane District |
| 1918 | Epidemic | | Influenza epidemic | Ontario |
| 1922 | Natural Disaster | 43 | Oct 4-5: A fire devastates Timiskaming District, killing 43. (learn more) | Timiskaming District |
| 1924 | Epidemic | 32 | Smallpox epidemic in Windsor results in 32 deaths | Windsor, Essex County |
| 1930 | Accident | 30 | Jun 26: The drill scow 'John B. King' explodes when lightening hit the dynamite carrying boat. Thirty crew members were killed. (learn more) | near Brockville, Frontenac County |
| 1939-1945 | War | 47,000+ | World War Two claims more than 47,000 Canadians | Europe |
| 1941 | Accident | 12 | Feb 6: Just outside Armstrong a Trans-Canada airplane bound for Manitoba crashes killing twelve. | Armstrong, Thunder Bay District |
| 1949 | Accident | 118 | Sep 16: A fire destroys the S.S. Noronic which was filled with sleeping American tourists (learn more) | Toronto, York County |
| 1950-1953 | War | 516 | Korean War claims 516 Canadians | Korea |
| 1953 | Accident | 20 | Jul 31: A bus crashes into a stalled trunk then plunges into the Williamsburg Canal, 20 drown | Morrisburg, Dundas County |
| 1954 | Natural Disaster | 83 | Oct 15: Hurricane Hazel hits Southern Ontario killing 83. Toronto is hardest hit. | Ontario |
| 1955-1975 | War | 133 | While Canada didn't officially participate in the war (other than to offer peacekeeping services in 1973), over 30,000 Canadians voluntarily served. This war claimed 133 Canadian lives. | Vietnam |
| 1956 | Accident | 15 | May 15: A fighter jet crashes into a convent killing everyone onboard as well as 11 nuns in the convent (learn more) | Orleans, Carleton County |
| 1959 | Accident | 8 | Feb 28: A Listowel arena collapses during a peewee hockey practice killing seven boys and their coach (learn more) | Listowel, Perth County |
| 1974 | Natural Disaster | 8 | Apr 3: A tornado causes the collapse of the Windsor Curling Club killing eight (learn more) | Windsor, Essex County |
| 1980 | Accident | 21 | Jul 14: A fire destroys a Nursing Home in Mississauga killing 21 (learn more) | Mississauga, York County |
| 1985 | Natural Disaster | 8 | May 31: An F4 tornado tore through Barrie killing eight (learn more) | Barrie, Simcoe County |
| 1989 | Accident | 24 | Mar 10: In Dryden a plane crashes just after takeoff killing 21 passengers and 3 crew members (learn more) | Dryden, Kenora District |
| 2001-2014 | War | 159 | As of 2016, 159 Canadians have been claimed by military actions in Afghanistan | Afghanistan |
