From my reading and talking to people it would seem like the best thing you can do is talk to Elders, check with Land Councils and look at this map but there could still be contentions around what is “correct” from person to person.
I also looked for Traditional names of certain areas and LGAs as opposed to postcodes. (I recently compiled a list of Country for where our venues are based)
@jacinta Would love to flag this with the Sendle team - have you had any experience looking into Traditional names? This could be an initiative for some of our B Corps working in the e-commerce space to collaborate on if they use Sendle. Perhaps starting with the larger cities (e.g. Naarm/Nairm is understood to be the Wurundjeri name for Melbourne) and working with Traditional Owners before finalising.
Also noting Ttobie’s comment - the AIATSIS map can be a great starting point, however they include this important note: The information on which the map is based is contested and may not be agreed to by some Traditional Custodians. The borders between groups are purposefully represented as slightly blurred. They do not claim to be exact.
We’ve also included the traditional place name for all of our branch locations on our website using the AIATSIS map and some further research to check local spelling etc.