Harwood Heights, IL has a population of 8,628 and is the 4,411th largest city in the United States. The population density is 10,461 per sq mi which is 4606% higher than the Illinois average and 11446% higher than the national average. The median age in Harwood Heights is 48 which is approximately 29% higher than the Illinois average of 37. In Harwood Heights, 57% of the population over 15 years of age are married, 38% speak English and 10% speak Spanish. 47% of Harwood Heights residents were born in Illinois, 5% were born out of state, 2% were born outside of the United States and 46% were foreign born.