
Mifflinburg
- County:
- Union County
- County Seat:
- No
- Area (mi²):
- 1.804
- State:
- Pennsylvania
Mifflinburg is a borough located in Union County, Pennsylvania. Mifflinburg has a 2025 population of 3,419. Mifflinburg is currently declining at a rate of -0.32% annually and its population has decreased by -1.55% since the most recent census, which recorded a population of 3,473 in 2020.
The average household income in Mifflinburg is $75,758 with a poverty rate of 3.47%. The median age in Mifflinburg is 37.9 years: 32.1 years for males, and 46.7 years for females.