The U.S. Postal Service is going ahead with plans to move the post office in the landmark Art Deco federal building and courthouse at Ninth and Market Streets to a storefront on the 700 block of Arch Street.

The first floor of what is today called the Robert N.C. Nix Sr. Federal Building andCourthouse has served as a post office known as the William Penn Annex since its construction 80 years ago.

"After consideration of the discussion and feedback, the Postal Service has announced it is moving forward on the proposal," the statement said.

The William Penn Annex will continue operations at the Nix building until the new facility opens at a date yet to be annouced.

The General Services Adminstation website offers this description of the post office at Ninth and Market:

As originally designed, much of the first floor is occupied by the William Penn Annex Post Office substation. The post office suite includes a Post Office Lobby along the Ninth Street (east) side of the building with a large Work Room and Loading Dock to the west. Monumental bronze-framed windows and public entrances dominate the north, east, and south walls of the Public Lobby. A black structural glass writing desk with semicircular aluminum incandescent desk lights alternating with aluminum plates for pen and ink stands runs continuously along the east exterior wall below the monumental windows. The suspended plaster ceiling is finished with aluminum leaf. The Post Office Lobby floor is three-tone terrazzo inlaid with bronze strips.

What will become of the space is not clear.

Nix Sr., who died in 1987, was the first African American to represent Pennsylvania in Congress.