In the paper, the least resource base required to ensure isolated human habitat sustainability over a historically long period of time is discussed. Territory and energy are proposed as such basic resources. The analysis of isolated societies of Tasmania, the Chatham Islands, and North Sentinel Island concludes that habitat can exist long and sustainably in a local area of at least 30 square kilometres in a mode of inherent safety, without the use of artificial technologies. This conclusion demonstrates the possibility of sustainable development of human civilization as a sum of local communities in the context of the isolationism paradigm, an alternative to globalism’s currently dominant concept. The significance of identifying the least resource base of sustainable development of isolated communities in the context of the establishment of scientific bases and settlements in remote areas of the globe, on the Moon and other planets of the solar system, and developing strategies to combat pandemics such as COVID-19, is highlighted.