Despite extensive research into the classic subfields of the hippocampus, the fasciola cinerea (FC), a medially located structure within the hippocampal formation, remains understudied. In order to gain insight into the unique features and potential functions of the FC, we examined the morphology, physiology, and connectivity of its principal neurons in anesthetized mice. Using in-vivo single-cell juxtacellular recording-labeling and quantitative morphometric analysis, we found that FC neurons exhibit unique firing patterns and dendritic architectures, which are distinct from principal cell populations in adjacent subfields. Viral neuronal tracing revealed that the FC receives afferent inputs from the entorhinal cortex but not from Schaffer collaterals, and contributes efferent projections to both intra- and extra-hippocampal targets. Notably, we report a novel FC projection to the septal CA2, a brain region important for social memory.Overall, our findings indicate that the FC is a morphologically and physiologically distinct subfield of the hippocampal formation, and its unique efferent connectivity points to a possible role in social memory.