United States Capitol Dome - First Dome

First Dome

The cast iron dome of the United States Capitol is not the first dome to sit above the building, but the second. The origin of the first dome began with the Capitol design contest sponsored by Secretary of State Thomas Jefferson, at the behest of President George Washington, in 1792. The winner of the contest, Doctor William Thornton, called for a dome in his original design for the building. Most vividly, Thornton drew upon the Roman Pantheon for inspiration with the Neoclassical dome and associated portico. However, Thornton never received the chance to build the dome he envisioned.

Nor, however, did Thornton's replacement as the second Architect of the Capitol, Benjamin Henry Latrobe, gain the opportunity to build the first dome for the Capitol. Rather, Latrobe was kept busy repairing, rebuilding, and completing the north and south wings of the building until his departure in 1817. Instead the job fell to Latrobe's successor, the third Architect of the Capitol, Charles Bulfinch. Bulfinch was responsible for the construction of the first dome in the nation, which he designed and built for the Massachusetts Statehouse in 1787.

Bulfinch began by adopting the suggestion of a drum, upon which the dome would sit, that was added to the Capitol designs by his predecessor, Latrobe. In contrast, however, the dome that eventually rose under Bulfinch's oversight was taller than any previous design and taller than his own preference. In an account written years later, Bulfinch stated that the dome was made loftier at the request of James Monroe's administration. In 1822, Bulfinch requested funds for the construction of the center of the building, and President Monroe signed off on an appropriation of $120,000. This included the building of a two-dome structure, a stone interior dome to rise 96 feet (29 m) above the rotunda floor (matching the dimensions of the Pantheon), and a wooden exterior dome that would rise to 140 feet (43 m). Set at the crown of the exterior dome was a 24 feet (7.3 m) wide oculus, which provided illumination to the rotunda floor below. Bulfinch completed the project in 1823.

For more than two decades, the green copper dome of the Capitol greeted visitors to the nation's capitol, until the 1850s. Due to the growth of the United States and the expansion and addition of new states, the size of the United States Congress had grown accordingly and pushed the limits of the capacity of the Capitol. Under the guidance of the fifth Architect of the Capitol, Thomas U. Walter, extensions were built onto the north and south wings of the building. In the process, the new, longer building made the original Bulfinch dome appear aesthetically displeasing (and had been the source of much prior criticism as well). Congress, after lobbying by Walter and Montgomery C. Meigs (then Supervising Engineer), passed legislation to build a bigger dome in 1855.