Washington Park, IL has a population of 4,029 and is the 7,420th largest city in the United States. The population density is 1,599 per sq mi which is 619% higher than the Illinois average and 1665% higher than the national average. The median age in Washington Park is 35 which is approximately 8% lower than the Illinois average of 37. In Washington Park, 35% of the population over 15 years of age are married, 98% speak English and 2% speak Spanish. 65% of Washington Park residents were born in Illinois, 35% were born out of state, 0% were born outside of the United States and 0% were foreign born.