The purpose of this qualitative study was to understand the meaning of living alone for older people with dementia. Fourteen audio-taped open-ended interviews were conducted with eight such older women in Ontario, Canada. The data were analyzed using an adaptation of van Manen's method. Heidegger's philosophy informed interpretation of the findings through the theme living on the threshold. The study findings deepen understanding of `space' and `place' in the experience of living alone with dementia. Participants sought the middle-ground of dialectical tensions within the threshold space and shared insights about their spatial experience of: (a) being here, (b) being there, (c) being out, and (d) keeping out. These older women risked losing their threshold space when admitting to mistakes as their illness progressed. The authors conclude with examples of how this spatial interpretation may inform and improve communication with and care of older people in similar circumstances.