Irwin is a city in Bonneville County, Idaho, United States.

According to the United States Census Bureau, the city has a total area of 2.45 square miles (6.35 km2), all of it land.

There were 166 housing units at an average density of 67.8 per square mile (26.2/km2).

25.2% of all households were made up of individuals, and 9.7% had someone living alone who was 65 years of age or older.

31.0% of all households were made up of individuals, and 15.5% had someone living alone who was 65 years of age or older.

About 3.5% of families and 9.7% of the population were below the poverty line, including 23.4% of those under the age of eighteen and none of those 65 or over.