Principal neurons with dendritic axon origins offer privileged pathways for information flow through the hippocampal network and between brain hemispheres. Traditionally overshadowed in research, the GABAergic interneurons play a crucial role in modulating network activity. Our research leverages genetic and immunofluorescent markers to dissect the morphological variance among inhibitory neuron subpopulations, focusing on the axon initial segments (AIS) — key sites for action potential generation. Our study captures the extensive diversity of proximal interneuron morphologies within the murine hippocampus and neocortex, highlighting spatial patterns and interactions guiding interneuron morphology as well as hitherto undescribed configurations of the AIS in hippocampal interneurons. By extending our analysis to human tissue both from pathological samples and surgical resections, we establish a comparative framework that can translate the relevance of our murine findings to human neuroanatomy. The spatial pattern of cells with dendritic axon origins suggests critical roles in hippocampal network dynamics and sets the stage for exploring its implications in human brain function.