Portland, IA has a population of 27 and is the 28,663rd largest city in the United States. The population density is 128 per sq mi which is 134% higher than the Iowa average and 41% higher than the national average. The median age in Portland is 56 which is approximately 47% higher than the Iowa average of 38. In Portland, 63% of the population over 15 years of age are married, 100% speak English and 0% speak Spanish. 70% of Portland residents were born in Iowa, 30% were born out of state, 0% were born outside of the United States and 0% were foreign born.