[3] Perry Township appears in the 1876 Atlas of Armstrong County, Pennsylvania.

According to the United States Census Bureau, the township has a total area of 15.0 square miles (38.9 km2), all land.

[3] As of the 2000 census,[11] there were 404 people, 154 households, and 119 families residing in the township.

19.5% of all households were made up of individuals, and 7.8% had someone living alone who was sixty-five years of age or older.

A portion of the Pennsylvania State Game Lands Number 105 is located in Perry Township, at the confluence of Birch Run with the Allegheny River.