Foundryville is a census-designated place (CDP) in Columbia County, Pennsylvania, United States.

The village is situated around Glen Brook, a southward-flowing tributary of Briar Creek and thence the Susquehanna River.

As of the census[9] of 2000, there were 265 people, 102 households, and 79 families residing in the CDP.

There were 107 housing units at an average density of 151.0 per square mile (58.3/km2).

18.6% of all households were made up of individuals, and 5.9% had someone living alone who was 65 years of age or older.

About 16.2% of families and 17.4% of the population were below the poverty line, including 22.2% of those under the age of eighteen and none of those sixty five or over.