Clinton, IA has a population of 26,148 and is the 1,650th largest city in the United States. The population density is 744 per sq mi which is 1262% higher than the Iowa average and 721% higher than the national average. The median age in Clinton is 42 which is approximately 11% higher than the Iowa average of 38. In Clinton, 56% of the population over 15 years of age are married, 97% speak English and 2% speak Spanish. 69% of Clinton residents were born in Iowa, 28% were born out of state, 0% were born outside of the United States and 2% were foreign born.