There has been a large-scale cessation of industrial activities in the region. The decrease in the population is associated with the decline of the steel-making industry in the "Mon Valley" which extends from Charleroi to the mouth of the Monongahela at Pittsburgh.
As of the census of 2000, there were 4,871 people, 2,258 households, and 1,208 families residing in the borough. The population density was 6,308.6 people per square mile (2,442.5/km²). There were 2,656 housing units at an average density of 3,439.9/sq mi (1,331.8/km²). The racial makeup of the borough was 95.32% White, 3.24% African American, 0.12% Native American, 0.29% Asian, 0.23% from other races, and 0.80% from two or more races. Hispanic or Latino of any race were 0.72% of the population.
There were 2,258 households out of which 22.3% had children under the age of 18 living with them, 35.5% were married couples living together, 13.7% had a female householder with no husband present, and 46.5% were non-families. 41.8% of all households were made up of individuals and 21.9% had someone living alone who was 65 years of age or older. The average household size was 2.11 and the average family size was 2.88.
In the borough the population was spread out with 20.5% under the age of 18, 7.1% from 18 to 24, 27.1% from 25 to 44, 20.2% from 45 to 64, and 25.0% who were 65 years of age or older. The median age was 41 years. For every 100 females there were 81.4 males. For every 100 females age 18 and over, there were 77.1 males.
The median income for a household in the borough was $23,593, and the median income for a family was $31,699. Males had a median income of $30,093 versus $23,873 for females. The per capita income for the borough was $13,752. About 16.1% of families and 21.3% of the population were below the poverty line, including 36.2% of those under age 18 and 13.7% of those age 65 or over.