Rock Mills, AL has a population of 558 and is the 18,890th largest city in the United States. The population density is 88 per sq mi which is 4% lower than the Alabama average and 3% lower than the national average. The median age in Rock Mills is 43 which is approximately 11% higher than the Alabama average of 39. In Rock Mills, 63% of the population over 15 years of age are married, 100% speak English and 0% speak Spanish. 47% of Rock Mills residents were born in Alabama, 53% were born out of state, 0% were born outside of the United States and 0% were foreign born.