Cairo, OH has a population of 470 and is the 19,911th largest city in the United States. The population density is 1,805 per sq mi which is 601% higher than the Ohio average and 1892% higher than the national average. The median age in Cairo is 41 which is approximately 3% higher than the Ohio average of 39. In Cairo, 62% of the population over 15 years of age are married, 100% speak English and 0% speak Spanish. 87% of Cairo residents were born in Ohio, 13% were born out of state, 0% were born outside of the United States and 0% were foreign born.