Marion, AL has a population of 3,507 and is the 8,044th largest city in the United States. The population density is 332 per sq mi which is 261% higher than the Alabama average and 266% higher than the national average. The median age in Marion is 22 which is approximately 43% lower than the Alabama average of 39. In Marion, 31% of the population over 15 years of age are married, 98% speak English and 1% speak Spanish. 81% of Marion residents were born in Alabama, 17% were born out of state, 1% were born outside of the United States and 1% were foreign born.