Manganese (Mn) is an essential metal for biological function; however, at high concentrations, it can become a potent neurotoxin. A proposed manganese mine near Emily, Minnesota, has prompted questions about potential impacts on local stream ecosystems. To establish a pre-mine ecological baseline, we examined the relationship between dissolved Mn concentrations and aquatic invertebrate community structure across four streams (CC, VS, LPR_N, and LPR_S). Invertebrates were sampled using standardized three-minute sweep-netting, and diversity metrics were quantified using species richness, evenness, and Shannon diversity. Contrary to our initial hypothesis that elevated Mn would reduce biodiversity, we observed a positive relationship between Mn concentration and both species richness and Shannon diversity, while species evenness showed no significant association. No meaningful relationships were detected between Mn and pH, temperature, nitrate, or iron levels. Due to the limited sample size, this experiment shows a non-representative snapshot of stream conditions rather than a comprehensive assessment. As such, the findings should be interpreted cautiously. A more extensive sampling radius and multi-season sampling are necessary to generate a representative understanding of manganese’s influence on aquatic community structure.