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

Pennsylvania Route 210 runs through the borough, leading 6 miles (10 km) southwest to U.S. Route 422 at Elderton and 6 miles (10 km) northeast to Plumville.

Keystone Lake, a reservoir on the North Branch Plum Creek, runs near the northwestern border of the borough.

19.0% of all households were made up of individuals, and 7.1% had someone living alone who was 65 years of age or older.

There were 18.2% of families and 10.6% of the population living below the poverty line, including 8.3% of under eighteens and none of those over 64.