The entorhinal cortex (EC) has been implicated in many functions related to spatial navigation, memory, and the perception of time. It is the major input and output pathway to the hippocampus, and this puts an enormous burden on the structure, as its networks decide what is processed in an area essential for episodic memory. Quantifying the building blocks of the entorhinal cortex (EC) is therefore a vital step in understanding the structure, as it provides major inputs and outputs to the hippocampus, a structure known for its memory functions. In the EC, the largest γ- aminobutyric acid (GABA)-ergic group of cells in the EC layer II are the parvalbumin (PV)-positive interneurons. PV+-cells have been shown to drive certain oscillations, and are functionally capable of sampling information from a large population of cells, and propagate information to a large number of neurons. The aim of the study was to quantify the PV+-cell population in the EC layer II. We identified a difference in PV+- cell population counts between the medial entorhinal cortex (MEC) layer II and the lateral entorhinal cortex (LEC) layer II. Specifically, the MEC LII showed a PV+-cell population that was consistently distributed from dorsal to ventral, while the LEC LII PV+-cell population declined when moving from dorsal to ventral. These tendencies were revealed in both the mouse and the rat, and reveals a trend that differs from some previous reports that showed a decline of PV+-cells in MEC when moving from dorsal to ventral. The tendencies also differ from findings obtained in humans and non-human primates. The dataset collected will be shared through the Human Brain Project.