The present Treasury
Building was built over a period of 33 years between 1836 and 1869. The
east and center wings, designed by Robert Mills, architect of the
Washington Monument and the Patent Office Building, comprise the first
part of the building constructed between 1836 to 1842. The most
architecturally impressive feature of the Mills design is the east
colonnade running the length of the building. Each of the 30 columns is 36
feet tall and is carved out of a single piece of granite.