La Grange, IL has a population of 15,688 and is the 2,733rd largest city in the United States. The population density is 6,218 per sq mi which is 2697% higher than the Illinois average and 6763% higher than the national average. The median age in La Grange is 40 which is approximately 8% higher than the Illinois average of 37. In La Grange, 63% of the population over 15 years of age are married, 87% speak English and 7% speak Spanish. 71% of La Grange residents were born in Illinois, 20% were born out of state, 1% were born outside of the United States and 8% were foreign born.