Louisville, KY has a population of 611,573 and is the 30th largest city in the United States. The population density is 2,319 per sq mi which is 2040% higher than the Kentucky average and 2460% higher than the national average. The median age in Louisville is 37 which is approximately 3% lower than the Kentucky average of 39. In Louisville, 50% of the population over 15 years of age are married, 91% speak English and 4% speak Spanish. 70% of Louisville residents were born in Kentucky, 22% were born out of state, 1% were born outside of the United States and 7% were foreign born.