Lilburn, GA has a population of 12,481 and is the 3,309th largest city in the United States. The population density is 1,952 per sq mi which is 1070% higher than the Georgia average and 2055% higher than the national average. The median age in Lilburn is 36 which is approximately 1% higher than the Georgia average of 36. In Lilburn, 54% of the population over 15 years of age are married, 56% speak English and 21% speak Spanish. 39% of Lilburn residents were born in Georgia, 27% were born out of state, 1% were born outside of the United States and 33% were foreign born.