Requiem For A Moderne Gem, William Penn Annex Post Office

September 22, 2016 | by Ann de Forest


Another great civic space yields to modern times. William Penn Annex Post Office on 9th Street is scheduled to close later this year. | Photo: Michael Bixler

It was a gloomy day two weeks ago when the U.S. Postal Service announced that it will close the William Penn Annex Post Office to customers later this year and relocate operations to the Cast Iron Building at 718 Arch Street. The Moderne-style building at 900 Market Street, a National Historic Landmark since 1990, will continue to house the Robert N. C. Nix Federal Courthouse and is in no imminent peril of being torn down. But the slim eastern section dedicated to mail service, a sleek and shiny high-ceilinged corridor accented with Art Deco trimmings, will no longer serve the function for which it was so intelligently and dynamically designed.  The closure of the post office highlights a disturbing trend: the ongoing degradation of customer experience as the quality of public interior architecture declines.

Pride and Populism

When the William Penn Annex Post Office first opened in 1937 the U.S. Postal Service was a finely-tuned, omnipresent communications network. In that year alone, the post office moved 25,801,279,00 pieces of mail across the country and around the world. Like public libraries and banks, post offices held a prominent position in every American city, town, village, or rural outpost. They served as the public’s portal—the user interface, as it were—that plugged U.S. citizens into this speedy, boundless transcontinental system. This particular portal on 9th Street, designed by Philadelphia architect Harry Sternfeld for the Ballinger Company, articulated and abetted that high-speed efficiency with elegance and grace, both inside and out.

Big, bas reliefs of regional mail carriers, titled North, South, East, and West, by public building sculptor Edmond Amateis remind passerby of a time when the postal service was America’s primary communications system. | Photo: Michael Bixler

At 9th and Chestnut Streets the sleek annex zips up against and under the solid, reassuring bulk of the steel and poured concrete courthouse like a train making a quick stop on its way out of town. The subtle, rounded corner evokes the streamlined nose of Pennsylvania Railroad’s S1 locomotive, which was making its debut over at 30th Street Station around the same time that the post office opened. But the reach and efficiency of the postal service depends on more than just machines, as Edmond Amateis’ four bas reliefs set in pink Milford granite and Indiana limestone on the 9th Street façade make clear. Depicted in the reliefs—North, South, East, and West—are four heroically muscular mailmen from the far reaches of North America delivering heavy loads in their regional garb, demonstrating that neither igloo nor cactus nor hefty haul of bananas can keep the postman from his daily rounds.

The interior is just as dynamic. A cadenced staccato of vertical lines—windows, columns, and service bays—plays against the glissando of long, shiny horizontals. The polished floor, gold-specked ceiling, and a black glass writing desk run the length of the building on one long continuous surface under the high, sunlit windows. The design is understated in performing its function, guiding customers through lines and to the appropriate service window. But here, form doesn’t merely follow function, it choreographs it. The long, slender dimensions and glossy surfaces encourage customers to glide glide dreamily through the minimalist space, senses attuned..

A sign of the times. Out of more than 45 postal service windows, only two are open on a typical weekday afternoon. | Photo: Michael Bixler

Sound is a factor as well. The high ceiling at once absorbs and amplifies conversation and movement. Spoken words are carried skyward into a genial hum that hovers like a cloud, while the click of footsteps on those polished floors resounds across the lofty walls of the small, slick canyon. Engaging eye and ear, the architecture of this Machine Age gem once elevated the mundane transactions of mailing packages or buying stamps into something civilized, dignified, and delightful.

How this building must have pulsed in its heyday, with the lights above those 42 aluminum-framed service windows flashing and their bells beckoning the next customer in line to move forward! Even now, with the building nearly empty of both customers and postal workers, and the lines moving at glacial speed, the high black-mullioned windows frame pedestrians as they move along the sidewalk, transforming the outside life of the street into animated urban cinema. One can imagine what that ever-looping film reel must have looked like when Market East was lined with department stores and shoppers streamed in and out of Strawbridge’s and Gimbel’s across the street.

The Decline of Place in Public Life

In this age of an ailing “snail mail” system, the rhythms of this once fast-paced, dynamic mailing machine have slowed to a stupor. The post office is often mostly vacant, and the wait is always long. Rarely do more than two of the triangular lights above those 42 chrome-framed windows flash. But waiting in line compels the 21st century customer to appreciate the building’s design, to contemplate the clever geometry and elegant proportions, even though the zing and flash of a noontime crush has been replaced by a church-like hush.

Limited services available. | Photo: Michael Bixler

Like typewriters, cassette tape players, and landline telephones, post offices have become nearly obsolete, a vestige of waning technology. Enriching experiences as exemplified by the William Penn Annex are becoming obsolete as well, heralding the death of energetic, utilitarian architecture and the prominent role it once played in public life.

Not all that long ago architecture’s most vital function was to shape and inspire our shared, public spaces. Banks, libraries, courthouses, train stations, schools, and post offices were all designed with an attention to proportion, detail, and a sensitivity to movement. Everyday commerce offered a succession of uplifting and enlivening experiences that are largely gone from contemporary life. Today, most quotidian errands take place inside interchangeable boxes. Often enough, post offices, banks, and retail stores inhabit joyless, generic spaces governed by moveable placards, room dividers, and two dimensional foam core displays. The shabbiness of modern commercial transactions leaves one wandering the aisles in morose complacency.

An Art Deco clock still keeps time above doors to the Federal courthouse. The service wall in the hallway of the post office resembles train cars speeding towards Market Street. | Photo: Michael Bixler

For those who argue that great architecture is a luxury, who associate the word with sumptuous (read: unaffordable) materials, fussy construction methods, and precious, aesthetic tricks, the post office at 9th and Chestnut offers a rebuttal. Built by the Work Progress Administration at the end of the Great Depression, this is a building that is both populist and minimal, yet delivers lots of bang for the buck. The interior designers delighted in incorporating commonplace materials like chrome, glass, and aluminum for dazzling effect. The spangly gold ceiling, for instance, is coated with aluminum leaf, essentially radiator paint. The beauty of the building lies not in its grandeur, but in its intelligence. The proportions, the geometric patterns, the juxtaposition of materials, show a human mind at work and is the source of the building’s dignity and humanity, its uplift and inspiration. We may no longer need the William Penn Annex Post Office to complete our daily rounds, but we could surely use the distinctive, stimulating generosity it once provided.


About the Author

Ann de Forest writes frequently about design, architecture, and the built environment. She is co-editor of Extant, the magazine of the Preservation Alliance for Greater Philadelphia. Her short stories, essays and poems have appeared in Coal Hill Review, Unbroken, Noctua Review, Cleaver Magazine, among others. She is the editor of Ways of Walking, an anthology of essays published by New Door Books in 2022, a project inspired by her having walked the entire perimeter of Philadelphia twice.


  1. Davis says:

    Great piece about a great place. Thanks!

  2. Richard Carle says:

    There has got to be all sorts of uses that space can be used for, especially if the wall of service windows can be removed. Maybe a restaurant, or a museum annex. Someone will come up with a great idea.

    1. Mike M. says:

      I vote for museum annex. The style and flavor of this building reminds me of the old Museum of Modern Art in mid-town NYC before that building went global in its expansion.

  3. James says:

    Who will take over the space now vacated by the Post office? If the space must be sublet to other parties, time to remove the art deco decorations for installation in other deserving buildings. Right now, I could imagine a museum setting for the customer service space but on what topic I will leave it to others to decide. What is behind the consume service space could be sublet to a data processing firm as those companies sometimes buy abandoned factory space to convert for such use.

  4. Jim Clark says:

    Wonderful article, thank you Ann.

  5. Robert says:

    This is sad. I have one personal connection with this building through the Architect, Mr. Harry Sternfeld. Mr. Sternfeld attended the First Presbyterian Churh in Germantown, and he would sit always behind my Mother and I, and after the service Mr. Sternfeld and my Mother would exchange pleasantries. I remember him as a kind and gentle man.

  6. MickR says:

    Great write up, but how sad. It has occurred to me I have not been in this post office – ! So I must make it a point soon. I used to look forward to going out to 30th street at midnight on April 15 because of the fabulous building. Guaranteed to be open for all us procrastinators.

    Yes the public realm has taken quite a beating. I think we’ve been doing a better job lately, but will we ever match such a level of civic pride such as this structure? I hope we can again.

  7. Stephen Perzan says:

    You can also find a write up about this building on the GSA website at:

    It also mentions there that the Building is Listed on the National register of Historic Places
    Landmark Status:
    National Register Listed

  8. Glen says:

    My father was a mailman there for 27 years, his route was Jewelers row. As a kid ,my dad would show his job to me and I was in the back mail area a couple of times. I have good memories of the place.

  9. Paul says:

    I was always a big fan of this place and recall the hardware at the north south desk wall matched other facets of the metalwork within which was pleasing to my uninformed eye.
    You may also recall the former PO at 30th and Market which is also sadly, no longer there (IRS offices now).
    That location at 30th Street also had a grand PO on the east end of the building with entrances on Market and Chestnut with large parabolic domes above the entryway lobbies. Having had a PO box there in the 80’s I remember walking through the lobby on non-rainy days and if you happened to walk in the center of either lobby you would be treated to an audio blast echoing your footsteps. It caught me by surprise one day and led to a life time of tapping my foot at the center of other parabolas I pass beneath.
    On rainy days the floor was covered with walk off mats that deadened the echo.

  10. KB says:

    The building is in good hands. The former post office space is currently under renovation to be transformed into a public facing passport processing office for the department of state (now located at 2nd and Chestnut). Extensive care has been taken to preserve the elements described above and maintain the original intent of the architects. Integration of the existing features into this new usage was a primary driver in many design decisions and hopefully provide due justice to its extensive history.

    (Stumbled on this article while in search of historic photos of the exterior)

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