Mercer is a very small borough located in the state of Pennsylvania. With a population of 1,955 people and three associated neighborhoods, Mercer is the 651st largest community in Pennsylvania. Mercer has an unusually large stock of pre-World War II architecture, making it one of the older and more historic boroughs.

Mercer’s overall crime rate ranks among the lowest in the nation, making it a very safe place to live.

Being a small borough, Mercer does not have a public transit system used by locals to get to and from work.

The education level of Mercer citizens, measured as those with bachelor's degrees or advanced degrees, is similar to the national average for all American cities and towns. 18.88% of adults 25 and older in Mercer have a college degree.

The per capita income in Mercer in 2022 was $34,621, which is middle income relative to Pennsylvania and the nation. This equates to an annual income of $138,484 for a family of four. However, Mercer contains both very wealthy and poor people as well.

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

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