CA2 and CA1 via the Schaffer collaterals. There are also a significant number of recurrent connections that terminate in CA3. Both the recurrent connections and the Schaffer collaterals terminate preferentially in the septal area in a dorsal direction from the originating cells. CA3 also sends a small set of output fibers to the lateral septum.

The region is conventionally divided into three divisions. CA3a is the part of the cell band that is most distant from the dentate (and closest to CA1).