In one experiment we examined the organizational structure of spatial memories for familiar environments, comparing it directly with that for unfamiliar environments. Participants in the familiar condition pointed from imagined perspectives towards objects in their own rooms and their performance was compared to that of matched controls in an unfamiliar condition who carried out the same task after studying the same rooms in immersive Virtual Reality. In both conditions, participants were faster and more accurate in pointing from imagined perspectives that were aligned with the geometry of the room (vs. not aligned), suggesting the presence of orientationdependent representations. Whereas in the unfamiliar condition pointing performance was best along a single axis, performance in the familiar condition was about equal across all 4 orientations that were aligned with the geometric structure of the room. Moreover, performance in the familiar condition was influenced by the orientation from which participants started to preview the room prior to testing; in contrast, in the unfamiliar condition performance was not influenced by the orientation from which encoding started. This finding suggests that post-encoding situational factors (e.g., the starting orientation from which an environment is previewed) can prime the accessibility of information in well-established long-term spatial memories.