The brackish water clam,Rangia cuneata, previously reported to occur from Virginia to the Gulf of Mexico, has been found in the Potomac River, Maryland, where they have been consumed for food. Current sampling of the population, compared with previous benthic surveys, indicates that the species has been established in the Potomac River only since about 1960. Introduction is believed to have been made along with seed oysters transplanted from the James River, Virginia.