The southern section, mainly facing E Street, is a marble structure three stories in height, set on a raised basement.

The building's public interior spaces on the south side exhibit characteristics of Robert Mills' design, including barrel-vaulted passageways.

During the War of 1812, Superintendent of the Patent Office William Thornton convinced British troops to spare the building when they burned down the District.

Following the destruction of the United States Capitol, members of Congress convened in Blodgett's hotel from September 1814 to December 1815.

[5] A fireplace accident set the building on fire in 1836, destroying thousands of patent models and records.

The US National Selective Service Board was a tenant in 1919, and it was here that US Army General John J. Pershing wrote his report on the American Expeditionary Forces in World War I.