Little information exists on macroinvertebrate community composition in small, micro-tidal, Ruppia maritima (widgeon grass)-dominated Maine estuaries. Qualitative and quantitative assessments of the macroinvertebrate fauna of widgeon grass beds in Northeast Creek estuary (Acadia National Park, ME) are presented here. The community was dominated by euryhaline freshwater invertebrates including midge larvae (Chironomidae: Dicrotendipes, Cricotopus, Chironomus), oligochaetes, damselfly larvae (Coenagrionidae: Enallagma), amphipods (Gammaridae: Gammarus), gastropods (Hydrobiidae: Hydrobia), ostracods (Cytheridae: Cyprideis), and water boatmen (Corixidae: Trichocorixa). Macroinvertebrate abundances at the sampled sites were 35,100 individuals/m² in both August and September, and 22,200 individuals/m² in October. This study provides baseline faunal-community data that can be used in future monitoring studies.