Mifflinburg, PA has a population of 3,533 and is the 8,004th largest city in the United States. The population density is 1,958 per sq mi which is 607% higher than the Pennsylvania average and 2062% higher than the national average. The median age in Mifflinburg is 44 which is approximately 8% higher than the Pennsylvania average of 41. In Mifflinburg, 61% of the population over 15 years of age are married, 96% speak English and 2% speak Spanish. 85% of Mifflinburg residents were born in Pennsylvania, 14% were born out of state, 0% were born outside of the United States and 1% were foreign born.