The cornerstone of the Capitol Power Plant was originally the pedestal for a statue of George Washington. Commissioned by the Congress from American sculptor Horatio Greenough (1805-1852), it was placed in the Rotunda of the U. S. Capitol in 1841. The statue was moved to the East Plaza of the Capitol in 1844 and remained on the East Front until 1908, when Congress approved its transfer to the Smithsonian Institution.
The marble pedestal, engraved with the words "First in War, First in Peace, and First in the Hearts of His Countrymen," was not transferred with the statue but taken to the site of the new Capitol Power Plant in Garfield Park, and in 1909 it was used as the cornerstone for the building. Greenough's statue is on display in the Smithsonian American History Museum.