When people learn an environment, they appear to establish a principle orientation just as they would determine the "top" of a novel object. Evidence for reference orientations has largely come from observations of orientation dependence in pointing judgments: Participants are most accurate when asked to recall the space from a particular orientation. However, these investigations have used highly constrained encoding in both time-scale and navigational goals, leaving open the possibility that larger spaces experienced during navigational learning depend on a different organizational scheme. To test this possibility, we asked undergraduates to perform judgments of relative direction on familiar landmarks around their well-learned campus. Participants showed clear evidence for a single reference orientation, generally aligned along salient axes defined by the buildings and paths. This result argues that representing space involves the establishment of a reference orientation, a requirement that endures over repeated exposures and extensive experience.