Clayton, AL has a population of 2,936 and is the 8,919th largest city in the United States. The population density is 434 per sq mi which is 372% higher than the Alabama average and 379% higher than the national average. The median age in Clayton is 38 which is approximately 1% lower than the Alabama average of 39. In Clayton, 34% of the population over 15 years of age are married, 97% speak English and 2% speak Spanish. 74% of Clayton residents were born in Alabama, 25% were born out of state, 0% were born outside of the United States and 1% were foreign born.