So I have seen a bunch of people make the (correct) point about how geographically isolated the insular peninsula is from the rest of Sydney which is true but I think there’s a broader point about much Sydney is divided up by geographic boundaries compared to other cities.

Sydney is surrounded by rivers, mountains and national parks, with a harbour and river down the middle. The northern beaches is mostly separated from the upper north shore by national parks and other bush land. Plus the Georges River separates the Shire.

In contrast Melbourne (and Brisbane) is mostly a flat plain divided by a single big river. I see this a lot when analysing options for electoral redistributions but I suspect it also plays out in how much people move around.

You can also see how Melbourne is more one big city and Sydney is a collection of small cities in sports teams. Melbourne sports teams mostly play in the inner city while Sydney teams are more dispersed.

I don’t know a lot about the Melbourne outbreak but this would have made it harder to do localised lockdowns compared to Sydney in general, particularly compared to the Northern Beaches.

Oh also, the Northern Beaches aren’t geographically ‘insular’ but it also refers to how people live there. And part of that is it’s a less accessible place. It’s easier to live there if you are wealthy and don’t need to commute or at least don’t need to use public transport.

This council area has no train lines and has resisted attempts to build train lines or improve the bus network. This lack of connectivity will surely help shut down this current outbreak.