This thesis is an investigation into the use of defensive architectural techniques by civilian settlers in frontier South Australia and the Northern Territory between 1847 and 1885. By focussing specifically on the civilian use of defensive architecture, this study opens a new approach to the archaeological investigation and interpretation of Australian rural buildings, an approach that identifies defensive strategies as a feature of Australian frontier architecture. Four sites are analysed in this study area, three of which are located in South Australia and one in the Northern Territory. When first built, the structures investigated were not intended, or expected, to become what they did - their construction was simply the physical expression of the fear felt by some of the colonial settlers of Australia. Over time, however, the stories attached to these structures have come to play a significant part in Australia’s frontier mythology. These structures represent physical manifestations of settler fear and Aboriginal resistance. Essentially fortified homesteads, they comprise a body of material evidence previously overlooked and unacknowledged in Australian archaeology, yet they are highly significant in terms of what they can tell us about frontier conflict, in relation to the mindsets and experiences of the settlers who built them. This architecture also constitutes material evidence of a vanguard of Australian colonisation (or invasion) being carried out, not by the military or police, but by civilian settlers. v Apart from this, these structures play a part in the popular mythology of Australia’s colonial past. All of these structures have a myth associated with them, describing them as having been built for defence against Aboriginal attack. These myths are analysed in terms of why they came into existence, why they have survived, and what role they play in the construction of Australia’s national identity. Drawn from, and substantiated through, the material evidence of the homesteads, these myths are one component of a wider body of myths which serve the ideological needs of the settler society through justifying its presence by portraying the settlers as victims of Aboriginal aggression.