Gardendale, AL has a population of 13,750 and is the 3,039th largest city in the United States. The population density is 598 per sq mi which is 550% higher than the Alabama average and 560% higher than the national average. The median age in Gardendale is 43 which is approximately 12% higher than the Alabama average of 39. In Gardendale, 68% of the population over 15 years of age are married, 97% speak English and 2% speak Spanish. 76% of Gardendale residents were born in Alabama, 22% were born out of state, 0% were born outside of the United States and 1% were foreign born.