Mercersburg is a very small borough located in the state of Pennsylvania. With a population of 1,493 people and two associated neighborhoods, Mercersburg is the 722nd largest community in Pennsylvania. Mercersburg has an unusually large stock of pre-World War II architecture, making it one of the older and more historic boroughs.

As is often the case in a small borough, Mercersburg doesn't have a public transportation system that people use for their commute.

The population of Mercersburg overall has a level of education that is slightly above the US average for all US cities and towns of 21.84%. Of adults 25 and older in Mercersburg, 22.35% have at least a bachelor's degree.

The per capita income in Mercersburg in 2022 was $39,173, which is upper middle income relative to Pennsylvania and the nation. This equates to an annual income of $156,692 for a family of four. However, Mercersburg contains both very wealthy and poor people as well.

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

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