Hippocampal volumetrics are becoming increasingly important for studying disease progression and diagnosis of temporal lobe epilepsy, Alzheimer’s disease, schizophrenia, post-traumatic stress disorder and major depressive disorder. However, comparing differences in volumetric variation across studies can be difficult due to differing anatomical boundaries, subject characteristics, statistical analyses and image processing techniques. In essence, inhomogeneity results from variance. One approach to this problem is to create a database of the homogeneous aspects of studies in order to get uniformity and comparative results. The Internet Brain Volume Database (IBVD) was created to provide a comparison of the homogeneous aspects of methods employed across different volumetric studies to begin to provide some uniformity and framework for comparison of different studies using volumetric measurements in morphometric analyses. As an example of this approach, the current study was designed to evaluate normal ranges of volumes in the hippocampus across published studies with similar manual methods and anatomical boundaries. The purpose of this review was to compare and evaluate region of interest (ROI) methods of volumetric analysis and generate a summary of trends and results. Twenty-two peer-reviewed studies involving ROI measurements of the hippocampus were surveyed for their methods and volumetric results and were selected if they included the hippocampal formation as the anatomical boundary and included a figural image of the boundary in the research article. This approach was chosen to reduce confusion over anatomical boundaries of the hippocampus and attempt to compare a more homogeneous sample of manuscripts at least in terms of anatomical definitions. Other sources of variance were also compared including subject characteristics, image processing techniques and volumetric software employed. Our results suggest a wide variance of volumes across studies for normal ranges of hippocampal volumes even when anatomical boundaries were essentially the same across studies. These results summarize and provide a review that suggests that anatomical boundaries, subject characteristics, slice thickness, image processing and image analysis can all affect volumetric measurements and should be carefully reported in manuscripts and compared among studies.