It initially consisted of the temporary judicial district of Nipissing, and the townships of Head, Clara and Maria in the county of Renfrew, and a part of the district of Algoma.
In 1903, it was redefined to consist of the territorial district of Nipissing, and the townships of Clara, Head and Maria in the county of Renfrew.
In 1914, it was defined to consist of the territorial district of Nipissing, the eastern part of the territorial district of Sudbury, and the townships of Clara, Head and Maria in the county of Renfrew.
Ontario is the most populous and second-largest in area of Canada's ten provinces.
Ontario's right to Northwestern Ontario was determined by the Judicial Committee of the Privy Council in 1884 and confirmed by the Canada (Ontario Boundary) Act, 1889 of the Parliament of the United Kingdom.
Ontario is bounded on the north by Hudson Bay and James Bay, on the east by Quebec, on the west by Manitoba, and on the south by the American states of Minnesota, Michigan, Ohio, Pennsylvania and New York.