[1] Since 1845, the city's main post office was located in the Middle Dutch Church on Nassau Street, a dark 18th-century building that by the 1860s was stretched past its capacity.

Five firms—Richard Morris Hunt, Renwick and Sands, Napoleon LeBrun, Schulze and Schoen, and John Perret—were selected to collaborate on a single design.

Together, the firms produced a Second Empire concept that borrowed from Renwick's Corcoran Gallery of Art and the New York State Capitol.

[5] Regarding the building's lack of popularity, The New York Times wrote in 1912: The Mullett Post Office has always been an architectural eyesore, and has, from the first, been unsatisfactory to the Postal Service and the Federal Courts beneath its roof.

Unfortunately, the cramped trapezoidal site required the post office's loading docks to be on the side facing City Hall and the park.