Stillwater, PA has a population of 214 and is the 24,135th largest city in the United States. The population density is 69 per sq mi which is 75% lower than the Pennsylvania average and 24% lower than the national average. The median age in Stillwater is 50 which is approximately 22% higher than the Pennsylvania average of 41. In Stillwater, 66% of the population over 15 years of age are married, 100% speak English and 0% speak Spanish. 83% of Stillwater residents were born in Pennsylvania, 17% were born out of state, 0% were born outside of the United States and 0% were foreign born.