as simple a question as you might think. History has conspired to make
any celebration of Victoria's Separation
After much local agitation, an act of British Parliament finally made provision for the separation of Port Phillip District from New South Wales. The long anticipated, often delayed, joyous news finally reached Melbourne (via the circuitous route of Adelaide newspapers) on the evening of 11 November 1850. Although the formal procedure of separation and inauguration of the Colony of Victoria remained dependent on the procedures of New South Wales Parliament, the locals would not allow mere formalities to stand in the way of long repressed anticipation. Full local celebrations in the form of a four-day official holiday (and much longer unofficial one) followed. Relatively speaking, it was arguably this State's greatest celebration.
The formalities of organising an autonomous Legislative Council for Victoria took the NSW Parliament a further seven months, with the official Separation occurring rather as an anti-climax on 1 July 1851. This date became known as Separation Day and was celebrated with increasing fervour for the remainder of the existence of the Colony. Federation (in fact the anticipation of it) ended the celebration, with Empire Day (24 May, commemorating the birth of Queen Victoria) and later Australia Day (26 January, commemorating the birth of Sydney) taking over.
Whilst 1 July is unquestionably the formal date of 'independence', 11 November has at various times in the past been considered the 'people's choice'. 11 November is also, for a number of reasons, Victoria's most historically significant date.
Victoria thus has either two dates, one date or even, as has so often been the case during its Statehood, no date at all to celebrate.