Mercer is a very small borough located in the state of Pennsylvania. With a population of 1,922 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.

A relatively large number of people in Mercer telecommute to their jobs. Overall, about 11.20% of the workforce works from home. While this may seem like a small number, as a fraction of the total workforce it ranks among the highest in the country. These workers are often telecommuters who work in knowledge-based, white-collar professions. For example, Silicon Valley has large numbers of people who telecommute. Other at-home workers may be self-employed people who operate small businesses out of their homes.

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

The percentage of adults in Mercer who are college-educated is close to the national average for all communities of 21.84%: 20.94% of the adults in Mercer have a bachelor's degree or advanced degree.

The per capita income in Mercer in 2022 was $38,162, which is middle income relative to Pennsylvania, and upper middle income relative to the rest of the US. This equates to an annual income of $152,648 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 Black or African-American. Important ancestries of people in Mercer include German, Irish, English, Polish, and Italian.

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