Northlake, IL has a population of 12,339 and is the 3,339th largest city in the United States. The population density is 3,895 per sq mi which is 1652% higher than the Illinois average and 4200% higher than the national average. The median age in Northlake is 34 which is approximately 9% lower than the Illinois average of 37. In Northlake, 53% of the population over 15 years of age are married, 41% speak English and 52% speak Spanish. 64% of Northlake residents were born in Illinois, 7% were born out of state, 1% were born outside of the United States and 28% were foreign born.