Charleroi is a very small borough located in the state of Pennsylvania. With a population of 4,159 people and two associated neighborhoods, Charleroi is the 367th largest community in Pennsylvania. Charleroi has an unusually large stock of pre-World War II architecture, making it one of the older and more historic boroughs.

The percentage of adults in Charleroi who are college-educated is close to the national average for all communities of 21.84%: 18.16% of the adults in Charleroi have a bachelor's degree or advanced degree.

The per capita income in Charleroi in 2022 was $27,138, which is low income relative to Pennsylvania, and lower middle income relative to the rest of the US. This equates to an annual income of $108,552 for a family of four. However, Charleroi contains both very wealthy and poor people as well. Charleroi also has one of the higher rates of people living in poverty in the nation, with 30.77% of its population below the federal poverty line.

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

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