Louisville, IL has a population of 1,084 and is the 14,638th largest city in the United States. The population density is 1,282 per sq mi which is 477% higher than the Illinois average and 1315% higher than the national average. The median age in Louisville is 44 which is approximately 16% higher than the Illinois average of 37. In Louisville, 63% of the population over 15 years of age are married, 97% speak English and 2% speak Spanish. 83% of Louisville residents were born in Illinois, 15% were born out of state, 1% were born outside of the United States and 2% were foreign born.