Macroinvertebrates play a vital role in assessing the ecological health of watersheds due to their sensitivity to environmental changes and abundance across diverse aquatic habitats. The abundance and diversity of these organisms have been used as critical biological indicators of water quality conditions. The Index of Biological Integrity (IBI), in particular, is a widely recognized tool for assessing aquatic ecosystem health, incorporating multiple metrics that reflect the macroinvertebrate richness, tolerance, and functional roles. However, IBI scores vary depending on ecoregions, sampling techniques, and protocols. In the United States, standardized protocols have been developed and adopted to provide consistent evaluation of watershed health, and most of them have been adopted from the U.S. Environment Protection Agency (EPA) Rapid Bioassessment Protocols (RBPs). Here, we review commonly used metrics in IBI calculation and explore IBI calculation and scoring among states, to examine key outcomes of various IBI measures on evaluating watershed health. We also reviewed benthic invertebrate data collected between 2008 and 2022 from the National Aquatic Resource Surveys conducted by the United States EPA. Macroinvertebrate abundance ranges considerably across lakes, rivers, and streams; however, commonalities in metrics were observed, providing some evidence of the potential for standardization in IBI scoring approaches. The future recommendation of the study would be standardization of IBI scoring across ecoregions, enhancement sampling techniques, integration of emerging technologies, such as incorporating environmental DNA (eDNA) into macroinvertebrate monitoring, and refinement of metrics used in IBI calculations. These recommendations aim to increase the role of IBI in safeguarding the watershed health of diverse aquatic ecosystems.