The Upper Delaware Scenic and Recreational River (UPDE) unit of the National Park Service partnered with the Academy of Natural Sciences of Drexel University (ANS) to perform a freshwater snail inventory within the park. ANS and UPDE teams conducted field research in July and August of 2022 and 2023 using a combination of kick sampling and hand-picking methods to determine the abundance and diversity of freshwater snail populations. Fifty-four sites were surveyed along the 73 miles of the Delaware River within UPDE and included cold-water and warmwater fisheries zones. In 2022, field collections occurred at 30 sites along the river edge from Hancock, NY to the No. 2 railroad bridge near Mill Rift, PA. In 2023, field work occurred at 24 sites in relatively disturbed areas and within unique river features that were not sampled in 2022. Snails were identified using traditional morphological taxonomy and DNA barcoding of the CO1 (Cytochrome c oxidase I) gene. Additional environmental DNA (eDNA) was analyzed from water collected at ten eDNA Atlas Sites. Based on genetic analysis, 27 species of gastropods were identified, one of which is a non-native species, the Japanese Mystery Snail (Cipangopaludina japonica); previous studies found 18 species and identified the mystery snail as the Chinese (Cipangopaludina chinensis). There were more snails below the Cannonsville Reservoir influence in the warmwater zone. A better understanding of the snail community and the ecosystem has been gained with the results of this inventory which will inform effective and responsible river management plans.