The Palearctic species Trechus obtusus Erichson is reported for the first time from eastern North America. Recent collections in Virginia and North Carolina (new state records) indicate the establishment of the species in the Appalachian region. DNA was extracted from six individuals, and the COI barcoding region was sequenced. All but one of the COI barcode haplotypes were identical to those of T. obtusus collected in western North America. No matches were found with available Palearctic sequences. Individuals of T. obtusus were collected from caves and forest leaf litter, both habitats used by native trechine species. Sampled Appalachian populations of T. obtusus appear to be small, with the exception of the population in Mebane Saltpeter Cave (Pulaski County, VA), which is large and included teneral individuals. Currently, there is no evidence that the species is displacing or otherwise negatively affecting native trechines. The species should be monitored carefully going forward, and targeted sampling of synanthropic habitats will be the best method for early detection.