U.S. Capitol’s cast-iron dome completed during the Civil War era

The current U.S. Capitol dome, designed by Architect of the Capitol Thomas U. Walter, was constructed in cast iron during the 1850s–1860s and was completed in 1866, replacing the earlier, smaller wooden dome. The cast-iron dome was painted to resemble masonry and its construction during the Civil War era is documented in congressional and architectural records. The dome remains a defining vertical feature of the Capitol building.