Clay City, KY has a population of 1,288 and is the 13,607th largest city in the United States. The population density is 1,216 per sq mi which is 967% higher than the Kentucky average and 1242% higher than the national average. The median age in Clay City is 34 which is approximately 11% lower than the Kentucky average of 39. In Clay City, 44% of the population over 15 years of age are married, 99% speak English and 1% speak Spanish. 85% of Clay City residents were born in Kentucky, 14% were born out of state, 0% were born outside of the United States and 1% were foreign born.