The eastern sand darter (Ammocrypta pellucida Agassiz) is a small (<7 cm) bottom dwelling fish that inhabits rivers with clean sand substrates. Siltation and degradation of its riverine habitat caused the species to become rare throughout its entire range, a geographic area originally extending from the St. Lawrence River and the Lake Champlain drainages to southwestern Ontario, southeastern Michigan, and throughout much of the Ohio River basin to eastern Illinois and south into Kentucky. Ammocrypta pellucida was documented as being abundant in the Maumee River (western Lake Erie drainage) in the late 1800s; but, with increased erosion and siltation in this basin, it has not been reported from the Ohio portion of the Maumee River mainstem since 1944. During field observations in Nov. 2009, we used seines and electroshocking to capture (and release) 18 A. pellucida from five 10 m² sites near Antwerp, Ohio. This represented the first record of this species in the Ohio portion of the Maumee River mainstem in 65 y. In Sept. 2010, using similar and standardized field techniques, a total of 24 eastern sand darters were observed in six out of twelve sites in 4.8 km of the Maumee mainstem. At least two age classes were present. Four 10 cm deep sediment cores were taken at each site and analyzed for particle size distribution and organic matter content. Eastern sand darter abundance was positively correlated with fish species richness, fish diversity, medium sand and medium fine sand substrates. Documented reductions in sediment load in the Maumee since the late 1970s, coincident with changes in upstream agricultural practices, may have helped reduce silt from sandy areas in the Maumee mainstem, promoting the recolonization by this silt-intolerant species from upstream refuges. Our results may help guide conservation efforts for this Species of Special Concern in Ohio.