Portland Township is one of sixteen townships in Cerro Gordo County, Iowa, USA. As of the 2000 census, its population was 331.
Portland Township covers an area of 32.42 square miles (84.0 km2) and contains a very small part of the city of Nora Springs (which lies mostly in Floyd County to the east). The unincorporated community of Portland, a census-designated place, is located in the western part of the township, just north of the Winnebago River. The county seat, Mason City, borders the township to the northwest.