North Irwin is a borough in Westmoreland County, Pennsylvania, United States.

[3] According to the United States Census Bureau, the borough has a total area of 0.2 square miles (0.52 km2), all of it land.

As of the census[5] of 2000, there were 879 people, 381 households, and 243 families living in the borough.

33.3% of all households were made up of individuals, and 13.9% had someone living alone who was 65 years of age or older.

In the borough, the population was spread out, with 22.5% under the age of eighteen, 8.1% from eighteen to twenty-four, 30.8% from twenty-five to forty-four, 22.5% from forty-five to sixty-four, and 16.0% who were sixty-five years of age or older.