Arlington is a neighborhood and census-designated place in the town of Poughkeepsie, Dutchess County, New York, United States. At the 2010 census, the CDP population was 4,061.Arlington is a suburb of the neighboring city of Poughkeepsie. It is part of the Poughkeepsie–Newburgh–Middletown, NY Metropolitan Statistical Area as well as the larger New York–Newark–Bridgeport, NY-NJ-CT-PA Combined Statistical Area.