Where to put Victoria’s 39th seat?


The latest ABS population figures for December 2019 were released yesterday, and they confirmed what we have suspected for some time. Victoria will gain a 39th seat at the next election, while Western Australia will lose its 16th seat and the Northern Territory (barring any legislative change) will revert to a single electorate.

In this post I will focus on how the addition of a 39th seat will likely shake up Victoria’s electoral map, including an interactive map showing each seat’s variation from quota. I will return on Monday with a similar analysis for Western Australia.

The Australian Electoral Commissioner is required to determine the entitlement of electorates in the House of Representatives for each state one year after the first sitting of the House, which this year will take place on July 3. The Commissioner uses the most up-to-date state population statistics, which will be the December 2019 data.

Victoria gained its 38th seat at the previous election, after holding steady at 37 seats for a long period of time. This means these electoral boundaries are relatively fresh. No seat is significantly out of line with the average. The most populous seat is 4.7% over the average (Ballarat) and the least populous is 5% below the average (Chisholm).

When you add a 39th seat, you lower the average seat size from 111,551 to 108,690. 30 of Victoria’s 38 seats are then at or above the average, with only a handful slightly below.

Every seat will have to be redrawn to create enough surplus voters to draw a new seat, and the impact will likely be statewide, but you can zoom out to the regions to get a sense of which areas will be hit hardest.

This table groups seats into four areas. I have split the state between Melbourne and rural Victoria, and then also split these areas into north-west and south-east.

RegionSeatsVariance from new quota
North-West Melbourne1026.5
South-East Melbourne1513.2
Eastern Victoria522.0
North & West Victoria838.4

There are 15 seats in Melbourne to the south-east of the Yarra. These seats are only slightly over quota: collectively 13.2% of an extra seat across these 15 seats.

So these seats shouldn’t require too radical changes. The individual seats range from +5% (Macnamara) to -2.5% (Chisholm). Outside of Macnamara, no other seat is more than 3% over quota. This area includes the seven least populous seats in the state, and all but one of the seats under the new quota.

There is more population growth in seats in central and western Melbourne, but most of the surplus lies in rural seats. The ten Melbourne seats to the north-west of the Yarra are collectively 26.5% of a seat over quota.

Some of the most populous seats lie to the west of Melbourne: Ballarat, Corangamite, Wannon and Bendigo are all 5% or more over quota, with Mallee not far behind.

So it seems most likely that the 39th seat will be drawn somewhere on the north-western fringe of Melbourne, absorbing surplus voters from these north-western rural electorates and the north-western half of Melbourne.

There is a natural divide through Victoria that runs from Port Phillip Bay, along the Yarra and then up through the Alps. The north-west half of the state, stretching as far to the east as Indi, includes 18 seats (10 in Melbourne, 8 outside Melbourne). This region has 65% of an extra quota’s worth of electors.

The Commission will usually try to avoid drawing electorates which cross the boundary. It seems likely the Commission will bring the north-west closer to a full quota by returning those suburbs on the north side of the Yarra which were moved from Jagajaga to Menzies in the last redistribution. This won’t make up 35% of a seat, but it might be enough to then just average out the differences across each half of the state.

Finally, here is the interactive map which you can click on to see the quotas for each electorate. Red seats are 1% or more under quota. Green seats are 1% or more over quota. Pale yellow seats lay in between.

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  1. Zac, I had no problems with Box Hill going into Deakin. A seat extending along the Maroondah Hwy and railway from Box Hill through to Ringwood/Croydon is a strong community of interest.

    DA, my plan is to put the southern tail of Calwell around the airport into Maribyrnong, with Fraser then pushing more clearly into the Footscray/Braybrook area. That pulls Gorton in and allows room for the new seat to take in Melton and BM. Putting the Macedon ranges into the new seat just made it, McEwen and Calwell too messy.

    DW, that’s very similar to how I’ve done it. I agree that once Holt and Latrobe are sorted out, everything falls into place fairly naturally to allow Menzies to expand. Although I’ve once again tried to realign Macnamara and Higgins either side of Williams Road/Hotham Street.

  2. Zac,

    This is my Deakin:
    1) Subtract everything north of the Maroondah Hwy (to Menzies)
    2) Add (from Chisholm) everything north of Canterbury Rd and east of Middleborough Rd (Blackburn, Blackburn North, etc.) These areas were part of Deakin prior to the last redistribution.
    3) Add (from Chisholm) Box Hill North.

    An alternative to (3) would be to add (from Chisholm) everything north of Highbury Rd and east of Blackburn Rd (uniting Forest Hill). This results in a more compact Deakin but less compact Chisholm.

  3. I had all the numbers, but then I looked at the actual map and I had Ballarat taking Golden Plains (except Linton which stays in Wannon), Ballarat and Hepburn with all of Moorabool in Gorton. But that was not acceptable, as Ballarat then wraps around Gorton and looked decidedly like the dreaded ‘G’ word.
    I managed to pull all of Kyneton out of Bendigo by expanding it into Nicholls, taking Rochester and some of Lockington. It means though that I’m making changes to Mallee, Nicholls and Indi, which all being in tolerance, I’d prefer to leave alone.
    I looked at just moving Kingsbury into Jajajaja which then leaves Menzies straddling the Yarra, and only taking a corrupt of Ringwood North SA1s.
    Then Deakin stretches into Box Hill, Chisholm goes south, Hotham into Noble Park and Bruce going to Narre Warren. But then that takes me back into Holt and La Trobe which I can’t find a good solution for. It’s annoying that there are so few major east-west roads in that area.
    I might look at some of the ideas here and see what works.

  4. I am also working on a proposal.
    I have managed to get all of non – Melbourne to work reasonably well. At present, I too am stuck in the outer south east trying to get Holt, Dunkley, La Trobe and Isaacs to work. I think at this stage, that La Trobe might need to move back further into the Dandenongs as I have too many voters in both Casey and Deakin.

    For what it is worth, my Deakin goes from Box Hill east and Chisholm becomes a City of Monash based seat. All of Menzies is south of the river.

    My proposal will abolish Hotham, and create two new seats – one in the west going from Melton / Bacchus Marsh and extending up to Kyneton taking almost of all of Macedon Ranges Shire. The other new seat is based on Narre Warren so Bruce shifts westwards.

  5. Long time numero-psepho, first time commenter here. Not a member of any party.

    Something I investigated but couldn’t resolve last time now seems to work… In the Gippsland region, we’ve essentially got two different communities of interest:
    – Former/current industrial towns that serve as commuter hubs with strong rail links to each other and Melbourne
    – “Sleepy” coastal towns highly reliant on January tourism.
    The sparsely populated hills in South Gippsland form as a natural barrier between these two types of communities.

    The current solution has been to split these two areas east-west. This invariably puts population growth pressure on Monash which absorbs new suburbs from Melbourne, and these areas have nothing in common with Leongatha, Foster, San Remo, etc.

    So an alternative that now just works is to instead have a north-south split. This puts all the SA2s of Phillip Island, Korumburra, Leongatha, Sale, Bruthen, Bairnsdale, Orbost into a single electorate. The coastal tourism focus is strong, with the whole area of the South Gippsland Highway and the Princes (in and east of Sale) forming a Gippsland electorate. This then creates a compact electorate that extends from most of Bunyip-Garfield right through to Rosedale, with this electorate firmly based around the Princes Highway and the train line. (I’ve also then chosen Koo Wee Rup to move to La Trobe for numbers).

    I’ve also tried a similar type arrangement up north to end the pretty poor alignment with Nicholls and Indi that both end up including urban-fringes as well as genuine rural and irrigation areas. This involves shoe-horning Shepparton and Wodonga into the one electorate (while the north-central of the state then takes the other electorate). This has knock on effects for the areas covered by Cobram through Kyabram and further up – it creates the possibility of creating a second lower Murray electorate through these areas. While I feel it will create room for Wannon and Ballarat to pivot NW, I haven’t yet finished this piece of the jigsaw.

  6. Hey @Truth Seeker. Good to see you over here. Are you blogging again? I was “Alaric” in the comments of your blog back during the 2013 WA Senate debacle.

    I’m in the write-up phase of my suggestions for Victoria. I didn’t touch Gippsland, Indi, Casey or Nicholls. I think they all make good sense considering LGA boundaries. Aston, Dunkley, Flinders, Goldstein, Kooyong and Scullin are also untouched.

    I found a La Trobe – Monash – Holt solution that I’m really happy with, albeit the Committee will probably refuse to do it because it involves a significant swap between La Trobe and Holt and requires Bruce to raid a handful of electors from Isaacs to provide enough flexibility further east.

    Hoping to get Victoria finished this weekend so I can move onto WA.

  7. I’m sceptical of reading ‘community of interest’ as ‘demography of interest’, not least because demographics are a proxy for voting habits. As if a community can’t be diverse. Redrawing Gippsland to be more homogenous demographically but more disjoint geographically is a questionable trade-off.

    In fact Gippsland used to skirt around the Latrobe Valley into South Gippsland. The pre-2004 redistribution decided, instead of further elongating the electorate, to make it more compact by adding Morwell & Traralgon. I think there was a general expectation that a future redistribution would see Moe-Newborough added to the seat. However, the numbers haven’t so far permitted this – partly due to the addition of extra seats in Victoria.

  8. I have some limited sympathy for something that might approach a “demography or interest” concept, and will be leaning on it to justify the split of Melton that is still in my suggestion, ahead of the alternative (within my wider solution) that would have seen a Calder Fwy division running from Keilor to Woodend. Although my argument is more precisely “look at the interests you bring together as much as the ones that you separate”.

    But certainly in rural areas, I’m always very reluctant to split LGAs. I haven’t fully tallied the outcome in that regard for my suggestion. Certainly some going each way – reuniting Colac-Otway but splitting Surf Coast. Reuniting Northern Grampians, but splitting Moorabool. Reuniting Cardinia. So maybe an improvement overall but I’m probably missing some.

    I agree that if Victoria ever has a redistribution that doesn’t involve a new division, Gippsland will likely pick up Moe, albeit it might need to lose some areas on the south coast to do so, as Moe is numerically a bigger bite than it will likely need from one redistribution to the next.

  9. Finally finished it. Despite some major changes needed, it all seemed to fall into place quite neatly in the end.

    I don’t look in detail into any political implications, but it seems to me that there’s very little that changes either way. Perhaps because the biggest changes are in the western suburbs (where it’s just swapping one set of safe Labor territory for another) and the east/south-east (where it’s mostly swapping one set of marginal territory for another).

    It will be interesting to see what other people have come up with, when the submissions are published.

  10. I’m in the final stages of my write-up. Hoping to finish today and then make a belated attempt at WA.

    Slightly annoyed at myself because I found a small non-optimal transfer that I’d included for numerical reasons, only to realise as I’m writing it up that I could have avoided it. But I’m too far down the track to tinker with maps now, so I’ve just referred to it as “not critical to the overall suggested scheme”.

    Otherwise I’m quite happy with how it’s come out. I have some really nice boundaries in the south-east, although they might represent the “courageous” option more than the minimalist one.

    No real feel for political implications. Maybe a slight nudge to Labor in a couple of marginals. I think the WA one will help Labor a lot – with the Liberal vote getting concentrated in seats they already win handily.

  11. Interesting that your WA proposal “helps Labor a lot”. As for Victoria, I didn’t get much change to the margins of the close seats despite significant boundary changes. A bit of like-for-like swapping once again, it seems.

    I look forward to reading your suggestions.

  12. I have a long way to go with my WA proposal and if it comes out like I expect, it won’t be because that was a target. Just a function of the fact that some under-quota strong Liberal seats are likely to get their top-up
    from Liberal parts of more marginal seats.

    Likewise looking forward to seeing the other Victorian suggestions.

  13. Had internet problems for a lot of today, only managed to submit my proposal at about 6:30pm. Here’s hoping they still accept it!

  14. Hello all,

    Long time follower of the ‘independents’ work. I’m perusing through all your proposals for VIC.

    Darren, it looks like the VEC don’t like links in their PDF files. Are you able to post your mapbox link here?

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