Ontario Military Records

Many useful military records are at the National Archives of Canada and the War Office in Great Britain; some are on microfilm at the Family History Library. The Wiki article Canada Military Records provides more information about Loyalist and British military sources.

Loyalists
Many of the Loyalists who arrived in Ontario beginning in 1784 had served in militia units attached to the British army. Until 1870, Canadian provinces were defended by units of the British army and navy.

Militia
During the 19th century, Ontario men between 16 and 60 years of age served in reserve units of local militia organized by county. Men reporting for militia duty were listed on annual muster rolls. Militia units were organized on a county basis. This system was replaced in 1855 with an active volunteer militia. It became the basis for the Canadian army. Militia members fought in military actions such as the War of 1812, the 1837 Rebellion, and the Fenian Raid of 1867, but records are few.
 * Men of Upper Canada: militia nominal rolls, 1828-1829 (Toronto: Ontario Genealogical Society, 1995) Family History Library, WorldCat: This volume reproduces the province-wide 1828-1829 muster roll — the most complete that was undertaken (the original records are held by Library and Archives Canada as RG 9, Series 1-B-2, vols. 29-31).
 * The Archives of Ontario has some muster rolls and militia records and published transcripts of muster rolls.
 * Some have been published in periodicals and books such as:
 * Bull, Stewart H. ''The Queen's York Rangers: An Historic Regiment', Erin, Ontario: The Boston Mills Press, 1984.  . WorldCat  Includes lists of officers of the York County militia in 1798, 1812, and 1837.
 * Additional militia returns are in the periodical articles listed in Brenda Dougall Merriman's Genealogy in Ontario, pages 184-85.(, WorldCat

World War I (1914-1918)
Canadian Expeditionary Force (CEF) service records are available through the Personnel Records Unit of the National Archives of Canada. These service records contain detailed information from enlistment to discharge. Information may include each person's date and pace of birth, address at time of enlistment, name and address of next of kin, marital status, occupation, personal description (eye and hair color, height, weight, distinctive marks or scars), and religion.
 * Personnel Records of the First World War, digital online.

Websites

 * http://www.bac-lac.gc.ca/eng/discover/military-heritage/Pages/military-heritage.aspx
 * http://www.warmuseum.ca/cwm/exhibitions/newspapers/intro_e.html
 * http://www.telusplanet.net/public/mtoll/militar4.htm