Ontario Naturalization and Citizenship
Until 1947, British immigrants from England, Scotland, Wales, and Ireland automatically became citizens of Canada. They did not need naturalization. Non-British immigrants, however, were required to make oaths of allegiance before receiving land grants. The oaths and petitions for citizenship for 1817-1846 are in files at the Provincial Archives.
Records created after 1917 are more detailed than earlier records and are found at:
Department of Citizenship and Immigration
Public Rights Administration
300 Slate Street, 3rd floor, Section D
Ottawa, ON K1A 1L1
Telephone: 888-242-2100 (In Canada only; outside of Canada, write to the above address.)
Ontario did not have a naturalization process until 1828. The National Archives of Canada in Ottawa has microfilm copies of naturalization papers for Upper Canada (Ontario) for 1828-1850. These are not at the Family History Library, but they are available through the interlibrary loan service to public libraries.
This index lists about 3,000 names:
McKenzie, Donald A. Upper Canada Naturalization Records 1828-1850. Toronto, Ontario: Ontario Genealogical Society, 1991. (FHL book 971.3 P42m; not on microfilm.)
Later naturalization records were maintained on a national basis by the office of the Secretary of State. See the Emigration and Immigration section of the Canada Research Outline (34545) for a detailed discussion on this topic.
There is a large database of Canadian immigrant records at www.ancestry.com ; this is a subscription website