According to the United States Census Bureau, the borough has a total area of 14.4 square miles (37 km2), of which 14.2 square miles (37 km2) is land and 0.3 square miles (0.78 km2), or 1.80%, is water. The landscape is largely hilly and wooded, and the borough's eastern boundary is contiguous with the Monongahela River three separate times. Much of the original landscape has been altered as a result of the historic dumping of steel mill byproducts such as slag and fly ash.
As of the census[11] of 2000, there were 22,464 people, 9,509 households, and 6,475 families residing in the borough. The population density was 1,586.2 inhabitants per square mile (612.4/km2). There were 9,966 housing units at an average density of 703.7 per square mile (271.7/km2). The racial makeup of the borough was 89.64% White, 8.85% African American, 0.12% Native American, 0.25% Asian, 0.06% Pacific Islander, 0.25% from other races, and 0.84% from two or more races. Hispanic or Latino of any race were 0.57% of the population.
There were 9,509 households, out of which 26.8% had children under the age of 18 living with them, 50.6% were married couples living together, 13.7% had a female householder with no husband present, and 31.9% were non-families. 29.0% of all households were made up of individuals, and 15.3% had someone living alone who was 65 years of age or older. The average household size was 2.35 and the average family size was 2.89.
In the borough the population was spread out, with 21.5% under the age of 18, 6.9% from 18 to 24, 26.2% from 25 to 44, 23.8% from 45 to 64, and 21.6% who were 65 years of age or older. The median age was 42 years. For every 100 females, there were 89.4 males. For every 100 females age 18 and over, there were 84.3 males.
The median income for a household in the borough was $36,130, and the median income for a family was $46,192. Males had a median income of $36,984 versus $26,529 for females. The per capita income for the borough was $18,140. About 8.8% of families and 10.2% of the population were below the poverty line, including 16.6% of those under age 18 and 9.1% of those age 65 or over. The unemployment rate is just over 6%.[12]
Environment
Coal mining in the area has affected the flow and water quality of small streams. Land developers have produced more level ground by clean-filling ravines and other small parcels of land to improve the land usage Toxic waste dump areas[13][14] are monitored with water quality improvement with bioremediation successfully implemented. West Mifflin operates its own sewage treatment facility. The Environmental Protection agency regulates 78 facilities for environmental compliance.[15] Asbestos waste and radioactive waste and controls were addressed in 1991.[16]
Seven schools exist in West Mifflin: four public schools and three private schools. West Mifflin public schools belong to one district-West Mifflin Area School District. School students in the neighboring boroughs of Whitaker and Duquesne also attend school in the West Mifflin School District.
There are two West Mifflin elementary schools, one West Mifflin middle school, one West Mifflin High School, and 13 West Mifflin preschools.
New England Elementary has been closed since June 2012. Saint Agnes School has been closed since June 2019. New Emerson has been closed since 2020. Prior to July 2016, Wilson Christian Academy existed at 1900 Clairton Road. It was merged into Cornerstone Christian Preparatory Academy, which is currently at that location.
West Mifflin school administrators' use of school credit cards for meals has been called into question.[22] The West Mifflin School District charges tuition for nearby Duquesne students to attend.[23]
D. R. Connors, Westinghouse Electric Corporation, Bettis Atomic Power Laboratory, West Mifflin, Pennsylvania, letter to R. L Pearson, Oak Ridge National Laboratory, Oak Ridge, Tennessee, "Update of Idaho Naval Reactor Facilities Miscellaneous Waste Inventory for the 1992 Integrated Data Base Report," dated May 5, 1992.