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. Much of the housing stock in Mercersburg was built prior to World War II, making it one of the older and more historic boroughs in the country.

Mercersburg is a small borough, and as such doesn't have a public transit system that people use to get to and from their jobs every day.

The citizens of Mercersburg are slightly better educated than the national average of 21.84% for all cities and towns, with 22.35% of adults in Mercersburg having a bachelor's degree or advanced 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.