Church in The Old House of Representatives

According to the Library of Congress:

Church services were held in what is now called Statuary Hall from 1807 to 1857. The first services in the Capitol, held when the government moved to Washington in the fall of 1800, were conducted in the "hall" of the House in the north wing of the building. In 1801 the House moved to temporary quarters in the south wing, called the "Oven," which it vacated in 1804, returning to the north wing for three years. Services were conducted in the House until after the Civil War. The Speaker's podium was used as the preacher's pulpit.

Learn more at the Library of Congress