Elderton is a borough in Armstrong County, Pennsylvania, United States.

According to the United States Census Bureau, Elderton has a total area of 0.31 square miles (0.8 km2), all land.

There were 156 housing units at an average density of 563.4 per square mile (217.5/km2).

The racial makeup of the borough was 99.44% White, 0.28% African American, and 0.28% from two or more races.

24.8% of all households were made up of individuals, and 10.3% had someone living alone who was 65 years of age or older.