Mount Gretna, PA has a population of 240 and is the 23,627th largest city in the United States. The population density is 1,665 per sq mi which is 480% higher than the Pennsylvania average and 1738% higher than the national average. The median age in Mount Gretna is 67 which is approximately 64% higher than the Pennsylvania average of 41. In Mount Gretna, 81% of the population over 15 years of age are married, 100% speak English and 0% speak Spanish. 48% of Mount Gretna residents were born in Pennsylvania, 52% were born out of state, 0% were born outside of the United States and 0% were foreign born.