1922: The township of North York was severed from the township of York.
1923: Forest Hill was incorporated on November 23, on land formerly in York township, which went into effect on January 1, 1924. The township of East York is severed from the township of York.
1925: Swansea was incorporated as a village from land formerly in York township.
1931: Long Branch was severed from Etobicoke township to become a village.
1953: Metropolitan Toronto was created as a new level of government
1967: A round of merging was conducted among the municipalities in Metro Toronto in 1967. The seven smallest municipalities of the region were merged into their larger neighbours, resulting in a six-municipality configuration that included the old City of Toronto and the surrounding municipalities of East York, Etobicoke, North York, Scarborough and York. Forest Hill and Swansea were annexed by the City of Toronto, Leaside was merged with the township of East York to become the Borough of East York. Weston was combined with the Township of York to form the Borough of York. The Village of Long Branch and the towns of Mimico and New Toronto merged with the township of Etobicoke to form the Borough of Etobicoke. North York township was promoted to the Borough of North York. Scarborough was also transformed into a borough.