Grant Park, IL has a population of 1,272 and is the 13,675th largest city in the United States. The population density is 373 per sq mi which is 68% higher than the Illinois average and 312% higher than the national average. The median age in Grant Park is 41 which is approximately 8% higher than the Illinois average of 37. In Grant Park, 63% of the population over 15 years of age are married, 94% speak English and 5% speak Spanish. 83% of Grant Park residents were born in Illinois, 12% were born out of state, 3% were born outside of the United States and 2% were foreign born.