The Eastern Bettong (also known as the Tasmanian or Southern Bettong) is only found in the wild in Tasmania. The mainland subspecies (Bettongia gaimardi gaimardi) became extinct in the 1920's. There are captive colonies of the Eastern Bettong at Tidbinbilla Nature Reserve and Mulligans Flat Woodland Sanctuary in the ACT.
Further references:
Bettongia gaimardi is listed in the following regions:
Canberra & Southern Tablelands
Species page sighting lists are under redevelopment and will return very soon.
Maps
Mulligans FlatPlaces
Forde, ACT Throsby, ACT