Steeles Avenue
In 1954, the communities south of Steeles Avenue was severed from York County, forming the Municipality of Metropolitan Toronto. As Armadale was situated along Steeles Avenue, it was split between the two county/regional governments. The portions of Armadale located south of Steeles Avenue became a part of Metropolitan Toronto, while the portion of the community north of Steeles Avenue remained a part of York County (reorganized into the Regional Municipality of York in 1971).