Franklin Grove, IL has a population of 1,060 and is the 14,791st largest city in the United States. The population density is 2,190 per sq mi which is 885% higher than the Illinois average and 2317% higher than the national average. The median age in Franklin Grove is 43 which is approximately 15% higher than the Illinois average of 37. In Franklin Grove, 67% of the population over 15 years of age are married, 96% speak English and 1% speak Spanish. 85% of Franklin Grove residents were born in Illinois, 13% were born out of state, 1% were born outside of the United States and 2% were foreign born.