The Warner Sand & Gravel Company, which bought the property in 1926, gave ten acres of land (including the site of Penn’s original house) to the Commonwealth of Pennsylvania. Over 1,000 attended the ceremony.

The State Archaeologist Donald Cadzow began digging at Pennsbury. Over the next four years, Cadzow’s team would locate the foundations of the Manor House, Bake-and-Brew, and front garden wall. Artifacts found in the archaeological investigations included bricks, shingles, glass, and other building materials.