Oakbrook Terrace, IL has a population of 2,453 and is the 9,960th largest city in the United States. The population density is 1,937 per sq mi which is 771% higher than the Illinois average and 2038% higher than the national average. The median age in Oakbrook Terrace is 40 which is approximately 7% higher than the Illinois average of 37. In Oakbrook Terrace, 55% of the population over 15 years of age are married, 74% speak English and 11% speak Spanish. 58% of Oakbrook Terrace residents were born in Illinois, 18% were born out of state, 1% were born outside of the United States and 23% were foreign born.