Spatial memories are often organized around reference frames, and environmental shape provides a salient cue to reference frame selection. These experiments explored the relative influences of two aspects of environmental shape on reference frame selection – room axes and wall surface orientations. Participants learned object locations within either a rectangular or elliptical room. The rectangular room contained axes aligned with wall orientations. Although the elliptical room also contained axes, straight walls were absent. Spatial memories acquired in the rectangular room were organized around a reference frame aligned with axes and walls. Spatial memories acquired in the elliptical room were also organized around a reference frame aligned with axes. These results indicate the influence of room axes on reference frame selection, even in the absence of straight wall surfaces. Subsequent experiments placed room axes in conflict with wall surface orientations to determine their relative contributions to reference frame selection.