Duncansville is a borough in Blair County, Pennsylvania, United States. It is part of the Altoona, PA Metropolitan Statistical Area. Duncansville is one of the communities that comprises the Altoona Urban Area. The population was 1,238 at the 2000 census.
Duncansville is located at 40°25′30″N 78°25′57″W / 40.425°N 78.4325°W / 40.425; -78.4325 (40.425072, -78.432435).
According to the United States Census Bureau, the borough has a total area of 0.5 square miles (1.3 km2), all of it land.