Sigara mathesoni (Hemiptera: Corixidae), which predominantly inhabits the northern United States and Canada, has recently been found in carbonate streams with stable and cold temperature regimes in south-central Pennsylvania. The focus of this research was to determine if there is a difference in occurrence of S. mathesoni between carbonate and non-carbonate streams, and whether abiotic factors within these habitats can be used to explain or predict its regional distribution. Our results suggest that S. mathesoni predominantly occurs in carbonate spring habitats, and that parameters such as alkalinity and daytime summer water temperature may best predict occurrence. This work validates observations in other literature and supports the hypothesis that S. mathesoni is a rare species in Pennsylvania and possibly throughout its southern range.