Gilman, IA has a population of 598 and is the 18,459th largest city in the United States. The population density is 1,105 per sq mi which is 1923% higher than the Iowa average and 1120% higher than the national average. The median age in Gilman is 42 which is approximately 11% higher than the Iowa average of 38. In Gilman, 71% of the population over 15 years of age are married, 100% speak English and 0% speak Spanish. 81% of Gilman residents were born in Iowa, 19% were born out of state, 0% were born outside of the United States and 0% were foreign born.