Chapin, IA has a population of 259 and is the 23,245th largest city in the United States. The population density is 2,628 per sq mi which is 4711% higher than the Iowa average and 2801% higher than the national average. The median age in Chapin is 33 which is approximately 13% lower than the Iowa average of 38. In Chapin, 35% of the population over 15 years of age are married, 100% speak English and 0% speak Spanish. 88% of Chapin residents were born in Iowa, 12% were born out of state, 0% were born outside of the United States and 0% were foreign born.