Division of Diamond Valley

The Division of Diamond Valley was an
Australian Electoral Division in Victoria. The division was created in 1969 and abolished in 1984. It was named for the Diamond Creek area. At the time of abolition, it was located in the north-eastern suburbs of Melbourne, including Doncaster, Greensborough, Eltham and Templestowe.
When it was initially created in 1969, the division replaced parts of the Division of Lalor and Division of Deakin. At the time, not only did it cover the Doncaster, Greensborough, Eltham and Templestowe areas, but it also covered an even larger area to the north, extending up to the towns of Whittlesea and Kinglake West outside Melbourne. In the 1977 redistribution, it lost most of these formerly-Lalor northern portions to the Division of Scullin, effectively shrinking its area by more than half. The redistribution was its only boundary change during its 15 years of existence.
With the expansion of the Parliament in 1984, the Division was abolished and split amongst multiple divisions:

majority of the division between Eltham North and Eastern Freeway formed the new Division of Menzies. This also included Eltham, Templestowe, Bulleen and Doncaster.
the portion north of Eltham North became part of Division of Casey
the portion west of Eltham became part of the new Division of McEwen
the portion west of the Plenty River became part of the new Division of Jagajaga

Always held by the government of the day, for most of its existence the seat was marginal between the Australian [Labor Party] and the Liberal Party. Its eastern half was strongly pro-Liberal, while its western half voted equally as strongly for Labor.