Shell Rock, IA has a population of 1,254 and is the 13,761st largest city in the United States. The population density is 803 per sq mi which is 1370% higher than the Iowa average and 787% higher than the national average. The median age in Shell Rock is 46 which is approximately 20% higher than the Iowa average of 38. In Shell Rock, 69% of the population over 15 years of age are married, 99% speak English and 0% speak Spanish. 86% of Shell Rock residents were born in Iowa, 12% were born out of state, 1% were born outside of the United States and 0% were foreign born.