The Amalgamation of Toronto
This map is based on the City of Toronto’s Annexation Map. The City of Toronto Archives have a high quality digital version of it here.
Wikipedia has a detailed timeline of Toronto’s amalgamation and annexations between 1791 and today.
Correction (Nov. 6, 2018): The map previously mislabelled Forest Hill as being annexed in 1924 – it was actually annexed in 1967. Thanks to Robin McLeod for identifying the error and letting us know.