The subgranular zone (SGZ) is a brain region in the hippocampus where adult neurogenesis occurs. It is one of the two major sites of adult neurogenesis in the brain, along with the subventricular zone (SVZ).

The subgranular zone is a narrow layer of cells located between the granule cell layer and hilus of the dentate gyrus. This layer is characterized by several types of cells, the most prominent type being neural stem cells (NSCs) in various stages of development. However, in addition to NSCs, there are also astrocytes, endothelial cells, blood vessels, and other components, which form a microenvironment that supports the NSCs and regulates their proliferation, migration, and differentiation.