Abstract: Alien plants have invaded forest habitats throughout the eastern United States (US) and may be altering native ant communities through changes in disturbance regimes, microclimate, and native plant communities. To determine if ant communities differ among sites with varying alien plant cover, we analyzed pitfall-traps and soil-core samples from a mid-Atlantic riparian forest located within a Us National Park. Only one alien ant species, Vollenhovia emeryi Wheeler, 1906 was found in this study. Total ant incidence and, to a lesser extent, richness were positively associated with the amount of alien plant cover. Species richness estimators also predicted more ant species within sites of greater alien plant cover. Increased ant incidence and ant richness appear to be the result of greater numbers of foraging ants in areas with greater alien plant cover rather than changes in the ant species composition. We suggest alien plant presence or other factors associated with alien plant cover have led to greater ant incidence and richness in these sites.