Portland is a town in Chautauqua County, New York, United States. The population was 4,366 according to the 2020 census. The town is on the shore of Lake Erie southwest of Dunkirk. The area was first settled in 1804. The town of Portland was founded in 1813 from the town of Chautauqua. Subsequently, the town was reduced in size to form tw…Portland is a town in Chautauqua County, New York, United States. The population was 4,366 according to the 2020 census. The town is on the shore of Lake Erie southwest of Dunkirk. The area was first settled in 1804. The town of Portland was founded in 1813 from the town of Chautauqua. Subsequently, the town was reduced in size to form two new towns: Ripley and Westfield.