Who designed the cast-iron dome of the U.S. Capitol, completed during the Civil War?

Thomas U. Walter designed the cast-iron dome of the U.S. Capitol, completed during the Civil War. Walter was the Capitol’s fourth Architect of the Capitol and oversaw the building’s major nineteenth-century expansion.

The original Capitol dome was a smaller copper-covered wooden structure designed by Charles Bulfinch. As the country expanded and Congress needed more space, Walter proposed a much larger dome as part of extensions to the House and Senate wings. Construction began in 1855, and the new dome was built from cast iron rather than masonry.

The dome was completed in December 1863, while the Civil War was still being fought. Its Statue of Freedom was installed at the top in 1865. Benjamin Henry Latrobe and Charles Bulfinch were important earlier Capitol architects, but neither designed the present dome. Walter’s design became an enduring symbol of the federal government continuing to function during wartime.