It was built by James Renwick Jr. in the Second Empire style in 1861, the second building in the history of what was one of America's first women's colleges.

At the time of its completion, the structure contained the most interior space of any building in the United States, and housed the entire college, including dormitories, libraries, classrooms, and dining halls.

At the center of the central portion is a projecting pavilion topped by a slate-roofed dome with iron cresting.

Window trim and horizontal banding on the building are of bluestone.

One notable exception is a large turning staircase in the central section, which was removed in 1893 as part of a library expansion that became known as "Uncle Fred's Nose", after Fred Thompson, whose name adorned the annex that was added at that time.