Oelwein, IA has a population of 6,195 and is the 5,638th largest city in the United States. The population density is 1,284 per sq mi which is 2250% higher than the Iowa average and 1317% higher than the national average. The median age in Oelwein is 44 which is approximately 16% higher than the Iowa average of 38. In Oelwein, 59% of the population over 15 years of age are married, 98% speak English and 1% speak Spanish. 80% of Oelwein residents were born in Iowa, 19% were born out of state, 0% were born outside of the United States and 1% were foreign born.