The political entity we now know as Ontario was originally created in 1791 when it was called Upper Canada. Since that time, in response to population growth and administrative needs, there have been numerous changes to its boundaries, both external and internal. In addition, townships, villages, towns and cities have frequently merged, and counties and districts have re-organized to meet changing needs.
The Archives of Ontario has prepared this guide to provide some background information about changes to Ontario's borders and political composition and includes maps and tables illustrating those changes.
People using records held by the Archives of Ontario can utilize the information in a variety of ways. For example:
Genealogists researching a mid-19th century marriage may need to know when counties replaced districts in a given geographical area.
A researcher concerned with pre-1867 records will need to be able to make the distinction between terms such as "Upper Canada, 1791", "Canada West, 1840" or "Province of Canada, 1867".
University students researching government policies regarding Northern Ontario will find it useful to know about the creation and role of districts in that area.
Local historians can use information about municipal re-structuring to locate a village that no longer exists as an independent entity.
Ontario's boundaries 1774-1912
Follow the evolution of Ontario's boundaries and name changes since 1774.
Early Districts and Counties
Starting in 1788, Districts and Counties became the regional level administrative units. This section details the growth and changes in county and district boundaries over time and briefly outlines the responsibilities of these two levels of administration.
Districts of Northern Ontario
This section follows the boundary changes in Northern Ontario since it was first divided into districts in the mid-19th century.
The Changing Shape of Ontario Home | Ontario's boundaries 1774-1912 | Early Districts and Counties
Districts of Northern Ontario | Post-World War II Regional Municipal Governments
Maps of Southern Ontario circa 1951 by County | Maps of Southern Ontario circa 1951 by Geographical Location
Municipal Restructuring since 1996 | Sources of Information