Irwin is a borough in Westmoreland County, Pennsylvania, United States. The population was 3,902 at the 2020 census. Located southeast of Pittsburgh, some of the most extensive bituminous coal deposits in the commonwealth are located in Irwin. In the past, iron foundries, flour mills, car shops, facing and planing mills, electrical goods and mirror factories were based in the borough.
History
Irwin was named for John Irwin, the original owner of the town site.
Irwin was the original western terminus of the Pennsylvania Turnpike when it opened in October 1940.
Brush Hill was listed on the National Register of Historic Places in 1975.
Geography
According to the United States Census Bureau, the borough has a total area of , all land.
Demographics
2020 census
As of the 2020 census, Irwin had a population of 3,902. The median age was 41.3 years. 18.2% of residents were under the age of 18 and 19.9% of residents were 65 years of age or older. For every 100 females there were 92.7 males, and for every 100 females age 18 and over there were 89.0 males age 18 and over.
100.0% of residents lived in urban areas, while 0.0% lived in rural areas.
There were 2,009 households in Irwin, of which 21.3% had children under the age of 18 living in them. Of all households, 32.7% were married-couple households, 25.2% were households with a male householder and no spouse or partner present, and 35.0% were households with a female householder and no spouse or partner present. About 44.1% of all households were made up of individuals and 16.1% had someone living alone who was 65 years of age or older.