Griswold, IA has a population of 1,176 and is the 14,152nd largest city in the United States. The population density is 1,894 per sq mi which is 3367% higher than the Iowa average and 1990% higher than the national average. The median age in Griswold is 40 which is approximately 6% higher than the Iowa average of 38. In Griswold, 62% of the population over 15 years of age are married, 98% speak English and 1% speak Spanish. 76% of Griswold residents were born in Iowa, 23% were born out of state, 0% were born outside of the United States and 0% were foreign born.