This is the oldest known photo of the U.S. Department of State. The photo is from 1857 and shows the old State Department building, before it was located in Foggy Bottom, and even before it was located in the State, War, and Navy Building next to the White House.
The building below is the old North East Executive Building, near the White House. Read more about the building at the State Department’s Office of the Historian.
Source: Library of Congress
The original executive buildings — State and Treasury on the east and War and Navy on the west — were modestly elegant and distinctly in the Federal style. I guess they had to go eventually, but it was a lovely ensemble while it lasted: the four departmental offices flanking the White House in the reservation designated “The President’s Park” by L’Enfant.
The four neo-classical Executive Office Buildings, including the old State Department, were designed by George Hadfield. For the old State Department see pp. 99, 100 (illus.), 101-2 and 207-8 in my book on George Hadfield: Architect of the Federal City.
What I find most interesting is, the windows on building IN BETWEEN the State Dept. and the building at the right of the photo. (Just a small glimpse) Long narrow windows, that are mostly seen in churches.