[2] In Tindale's estimation the Iwaidja possessed some 100 square miles (260 km2) of tribal lands.
Foelsche informed Edward Micklethwaite Curr that: The country frequented by this tribe extends from Raffles Bay to Port Essington Harbour and thence midway up the Cobourg Peninsula to Popham Bay.
[a] Four other groups were reported to share the same territory, though for Tindale their status as either hordes or independent tribes was undetermined.
They were listed as: If we take the Unalla as interchangeable with the Iwaidja, they were a once numerous tribe which, with the onset of colonial settlement, was reduced to a mere 30 members by 1881, consisting of 7 men, 12 women, 9 boys and 2 girls.
Foelsche stated that the community was ravaged after Malay traders introduced smallpox during a visit in 1866.