Addison, IL has a population of 37,192 and is the 1,118th largest city in the United States. The population density is 3,816 per sq mi which is 1616% higher than the Illinois average and 4111% higher than the national average. The median age in Addison is 35 which is approximately 6% lower than the Illinois average of 37. In Addison, 57% of the population over 15 years of age are married, 46% speak English and 35% speak Spanish. 58% of Addison residents were born in Illinois, 6% were born out of state, 1% were born outside of the United States and 34% were foreign born.