Clay, KY has a population of 1,052 and is the 14,838th largest city in the United States. The population density is 1,221 per sq mi which is 1026% higher than the Kentucky average and 1247% higher than the national average. The median age in Clay is 40 which is approximately 3% higher than the Kentucky average of 39. In Clay, 64% of the population over 15 years of age are married, 100% speak English and 0% speak Spanish. 76% of Clay residents were born in Kentucky, 24% were born out of state, 0% were born outside of the United States and 0% were foreign born.