Lewis, IA has a population of 553 and is the 18,957th largest city in the United States. The population density is 1,106 per sq mi which is 1924% higher than the Iowa average and 1120% higher than the national average. The median age in Lewis is 44 which is approximately 17% higher than the Iowa average of 38. In Lewis, 68% of the population over 15 years of age are married, 98% speak English and 1% speak Spanish. 62% of Lewis residents were born in Iowa, 38% were born out of state, 0% were born outside of the United States and 0% were foreign born.