Portlandville is a hamlet (and census-designated place) in Otsego County, New York, United States. As of the 2020 census, Portlandville had a population of 177. The community is located along the Susquehanna River and New York State Route 28, northeast of Oneonta. Portlandville has a post office with ZIP code 13834, which opened on April 9, 1828. References