Arnold City, PA has a population of 546 and is the 19,029th largest city in the United States. The population density is 1,217 per sq mi which is 339% higher than the Pennsylvania average and 1243% higher than the national average. The median age in Arnold City is 58 which is approximately 43% higher than the Pennsylvania average of 41. In Arnold City, 46% of the population over 15 years of age are married, 93% speak English and 7% speak Spanish. 89% of Arnold City residents were born in Pennsylvania, 11% were born out of state, 0% were born outside of the United States and 0% were foreign born.