Mifflinburg is a very small borough located in the state of Pennsylvania. With a population of 3,462 people and two associated neighborhoods, Mifflinburg is the 434th largest community in Pennsylvania.

The citizens of Mifflinburg are slightly better educated than the national average of 21.84% for all cities and towns, with 23.71% of adults in Mifflinburg having a bachelor's degree or advanced degree.

The per capita income in Mifflinburg in 2022 was $32,492, which is middle income relative to Pennsylvania and the nation. This equates to an annual income of $129,968 for a family of four. However, Mifflinburg contains both very wealthy and poor people as well.

The people who call Mifflinburg home describe themselves as belonging to a variety of racial and ethnic groups. The greatest number of Mifflinburg residents report their race to be White, followed by Black or African-American. Important ancestries of people in Mifflinburg include German, Italian, Irish, English, and Polish.

The most common language spoken in Mifflinburg is English. Other important languages spoken here include Italian and Polish.