The primary output pathway of the hippocampus is provided by the pyramidal cells of the subiculum. Here, analysis of mouse subiculum using single-cell RNA sequencing revealed widespread differences in gene expression that could be mapped onto eight distinct subpopulations of pyramidal cell. Further analysis with in situ hybridization showed that these subclasses were spatially partitioned into specific domains that corresponded to specific downstream projection targets. This more detailed picture of the complex landscape of the subiculum is likely to aid future study of this area.