This building was designed in the office of the Architect of the Treasury, James Knox Taylor, as a post office and federal building. Taylor's office provided Ottumwa with one of the state's finest and most sophisticated versions of the Beaux-Arts Classical style. The three-story building exhibits a rusticated first floor, a second floor defined by thin pilasters, and a third floor as an attic. All of the windows and doors on the first floor are arched, suggesting an enclosed loggia; the rectangular windows of the second floor are accompanied by pediments set within arched openings; the square windows on the third floor are simply set deeply into the wall. The most impressive facade of the building is at the rear, where the building works itself into the hillside via a T-shaped staircase.