Marquette, IA has a population of 423 and is the 20,559th largest city in the United States. The population density is 244 per sq mi which is 346% higher than the Iowa average and 169% higher than the national average. The median age in Marquette is 45 which is approximately 18% higher than the Iowa average of 38. In Marquette, 50% of the population over 15 years of age are married, 99% speak English and 1% speak Spanish. 41% of Marquette residents were born in Iowa, 58% were born out of state, 0% were born outside of the United States and 1% were foreign born.