Robert N. C. Nix, Sr. Federal Building and U.S. Courthouse, Philadelphia, PA

(Adapted from the Historic Structure Report compiled by John Milner Associates, Inc., October 1989.)


The Robert N. C. Nix, Sr. Federal Building and Post Office is located at the southwest corner of Ninth and Market Streets in downtown Philadelphia, Pennsylvania. It is situated on a rectangular lot measuring approximately 2 acres in size and encompassing nearly half of a city block. The lot is bounded by Market Street to the north, Ninth Street to the east, and Chestnut Street to the south. An alley on the west side of the property provides access from Market Street to the building's loading dock and limited on-site parking.

The building rises seven stories above grade to a height of approximately 115 feet including a full basement, a partial mezzanine level between the first and second floors, and two rooftop penthouses. Its footprint is generally rectangular in shape and measures approximately 170 feet east-to-west by approximately 470 feet north-to-south. An open light court situated above the third-floor level provides ventilation and light to offices located to the north, south and east, and to a mechanical space located to the west at the fourth floor. The building is shaped like a capital "C" at the fifth- and sixth-floor levels, open to the west with office space to the north, south, and east.

Original construction drawings indicate that the foundations are constructed of reinforced concrete spread footings. Basement walls are comprised of reinforced concrete and floors are concrete slabs on grade. Elsewhere, the building employs a steel structure encased in concrete with interior walls and partitions of poured-in-place concrete, structural clay tile, and brick.


The exterior of the building is clad primarily in Indiana limestone above a base faced with Milford pink granite. Secondary facades at the building's interior light court and at the west facade also utilize buff-colored brick. The building's flat roofs are concealed from the street by stone parapets.

The vertical organization of the exterior of the building generally follows a tripartite composition, based on a stylized version of the stylobate, column, and entablature characteristic of Classical architecture and adapted to the Art Deco style representative of the period. At the principal facades, the first story of the building reads as the base for the upper floors. It is faced with ashlar limestone blocks set with narrow mortar joints above a continuous base of smooth granite that also forms the sill of the first-floor windows. This portion of the facade is interrupted by monumental bronze windows and large rectangular monolithic blocks of granite that project outward, flanking the principal public entrances.

The Market and Chestnut Street facades both feature centrally located entrance doors flanked by large, rectangular, granite bas-relief sculptures representing symbols of law and justice. The Ninth Street facade is symmetrically arranged with four entrances to the first-floor Post Office Public Lobby; the northernmost and southernmost entrances both feature banks of four doors each while the two central entrances are equipped with revolving doors. Two pairs of granite bas-relief sculpture depicting the activities of postal carriers in various regions of the United States also flank the northernmost and southernmost entrances along Ninth Street. Centered between the two revolving door entrances, a series of thirteen bas-relief medallions representing the seals of the first thirteen states to ratify the Constitution of the United States is carved into the limestone facade above the monumental first-story windows.

Stepped back from the perimeter of the first-story base, a rectangular tower block rises five additional stories. Metal windows typically alternate with aluminum spandrel panels in vertical bands from the second through sixth floors of this tower block. These vertical window bands in turn are spaced between vertical limestone wall panels ornamented with three continuous carved flutes. Rather than employing a traditional entablature, the primary facades of the building are capped by a flush parapet wall with minimal ornamentation: three bas-relief carved fasces, the ancient Roman symbol of authority and power, are centered in the frieze over the central window bays at the Market (north) and Chestnut Street (south) facades; and carved panels containing three horizontal bars are positioned above each of the vertical window bays along the Ninth Street (east) facade.

The exterior appearance of the building has changed very little since its construction. Archive records indicate that more than 270 window air-conditioning units had been installed within the original hopper window sash on the upper floors. The individual air-conditioning units have since been removed and the window sash and frames were replaced during the 1990s with aluminum units designed to match the original window configurations. The easternmost entrance on Market Street has also been altered to accommodate access for the physically challenged.



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.

A wall divided into nineteen bays separates the public and private areas of the first-floor Post Office. The bays at the extreme north and south ends of the wall have openings to the passages connecting to the two Elevator Lobbies. The seventeen intervening bays feature large six-light transom windows with prism glass infill above a series of door and window openings. The typical postal service windows include stainless steel countertops, mill-finish aluminum jambs and head frames, sliding aluminum bar grilles, and upward-sliding aluminum sashes with patterned glass. Triangular-shaped illuminated directional signs are mounted above each service window. Several service windows at the middle of the Post Office Lobby have been modified to accommodate new pass-through windows and self-service postage machines. The original aluminum lock boxes, frames and trim have been removed from the Post Office Lobby and replaced with natural finish aluminum boxes of a more contemporary design.

The former Parcel Post Lobby located at the north end of the Post Office Lobby has been subdivided to create space for new lock boxes. The three-tone terrazzo floor pattern and wall finishes are similar to those in the Post Office Lobby. Black, glass-topped writing desks remain along the east wall and in the center of the room. Behind the new lock boxes, a stainless steel counter with built-in scale wells remains along the west and south walls. An original stainless steel, aluminum, and glass directory also survives on the west wall.

The Post Office Work Room has been subdivided over the years to accommodate various programmatic changes. The extant Work Room features varnished wood floors, glazed tile and painted wood wainscot, painted plaster perimeter walls, some painted plaster ceilings, and suspended linear fluorescent light fixtures. Wire mesh partitions separate various Post Office service groups. The east side of the room contains the service windows. At the south end of the space are two walk-in storage vaults with concrete floors, painted plaster walls and ceilings, suspended fluorescent light fixtures, and painted steel vault doors. An integral part of the Post Office Work Room is the suspended look-out gallery, which, with several cross galleries, makes a continuous circuit around the perimeter of the Work Room, and continues to serve its original function. Several hatches provide access from the Mezzanine level.

The west side of the Work Room has a series of offices and service lobbies which communicate directly with the Post Office Loading Dock. Typical finishes in these offices include wood floors, glazed brick wainscot with painted plaster walls above, unfinished ceilings, and suspended fluorescent light fixtures. Doors to the service lobbies are typically paired double-acting, painted, hollow metal doors and frames. Typical finishes in the service lobbies are similar to those in the offices.

In the far northwest corner of the first floor is the bulk mail pick-up and delivery lobby. Typical finishes include terrazzo floors, glazed brick wainscot, painted plaster walls and ceilings, paired double-acting, painted, hollow metal doors and frames, and ceiling-mounted fluorescent light fixtures.

The south end of the original Post Office Work Room has been modified to accommodate a parking garage and the regional office of the National Archives and Records Administration. Typical finishes in the National Archives spaces include original wood, vinyl tile and carpet flooring, vinyl base, painted drywall partitions, painted hollow metal doors and frames, suspended lay-in acoustical tile ceilings, and fluorescent lighting fixtures.

The first-floor Mezzanine, located at the northwest side of the building above the Post Office Work Room, is used by the Post Office for men's and women's locker rooms, toilet rooms, and a shift room. Typical finishes include terrazzo floors (with an epoxy floor coating introduced in some locations), glazed brick wainscot, painted plaster walls and ceilings, and painted hollow metal doors and frames. Hatches from the first-floor Mezzanine provide access to the look-out gallery within the Post Office Work Room.

The two first-floor elevator lobbies, located at the north and south ends of the building, are rectangular spaces with walls clad in flush, butt-jointed, marble panels. The floors of the elevator lobbies are comprised of three-tone terrazzo panels separated by bronze divider strips in several widths. Flat, suspended plaster ceilings are finished with aluminum leaf. Entrance vestibules are situated between the elevator lobbies and the Market and Chestnut Street entrances. The vestibules are rectangular areas and contain three sets of triple bronze doors set in bronze frames. A square transom is situated above each set of triple doors. Located opposite the entrance doors are the elevator banks, over which are bas-relief sculptures of an eagle flanked by the seals of the United States, the Treasury Department, the Department of Justice, and the Post Office Department. The east walls of both first-floor elevator lobbies feature square unornamented openings leading to the Post Office Public Lobby; passages to the west lead to the main stair towers.


The Courtrooms and Law Library are located on the second floor. According to the original design, these rooms are insulated from the surrounding office space. Each of the courtrooms is a double-height space with public entrances on the west side. A small vestibule separates the courtrooms from the Public Corridor.

Floors in the courtrooms, originally finished with cork tiles organized in a pattern of squares and rectangles created by the use of varying tones, typically have been replaced with contemporary carpeting or a raised flooring system. Walls in Courtroom Nos. 2 through 7 are paneled with red cedar and also feature walnut pilasters, decorative fluting, and ornamental wood moldings. Double-leaf doors between the vestibules and courtrooms are leather-covered with metal studs and bronze kick plates. Each leaf contains three small rectangular glass lights. Typical judges’ benches are constructed of wood with walnut veneer and are treated as an ensemble including a court clerk’s desk, judge’s desk, witness stand, flag pole base, and lectern. Jury boxes stand independent, but are detailed similarly.

The double-height Law Library, located on the south end of the second floor has a public entrance from the Public Corridor as well as an entrance from the Private Corridor. Typical finishes include carpeted floors, painted plaster on the north and south walls, and cedar paneling on the east and west walls similar in detail to that in the courtrooms. The original bookcases and library desks remain in place. Various ancillary spaces including the librarian's office, a conference room, and storage areas comprise the remainder of the suite.


The third, fourth, fifth and sixth floors have been renovated multiple times to accommodate the needs of various tenant groups. Presently, these four floors present a collection of office suites, interconnecting office rooms, and open plan office spaces. Interior finishes typically include carpeted floors, marble, wood, and vinyl cove bases, gypsum wallboard partitions, suspended acoustical ceiling tile systems, and various wood veneer and hollow metal doors set in metal frames.

Elevator lobbies on the third through sixth floors are similar in detail and finishes to those on the first and second floors. Floors are typically terrazzo. Walls are typically painted plaster with marble base and marble architraves surrounding elevator and other door openings. Ceilings are typically painted plaster with circular incandescent light fixtures set flush with the ceilings.


The basement level serves primarily as storage and mechanical space. Basement finishes are generally utilitarian in response to location and use. Painted finishes predominate and include exposed structural concrete perimeter foundation walls, concrete-encased steel columns, concrete masonry unit and brick partition walls, and concrete floors. Suspended ceilings are present in some locations and lighting is typically provided by suspended fluorescent and incandescent fixtures. Doors and frames are typically painted hollow metal.


The internal circulation of the building follows a simple and direct arrangement with elevator lobbies located on all floors at the Market and Chestnut Street ends of the building connected by at least one circulation corridor. On the first floor, the Post Office Public Lobby serves as this connection along the Ninth Street (east) side of the building. At the second floor, the Public Corridor along the west side of the building provides access to the interior courtrooms. Circulation patterns at the third floor are similar to those at the second floor. On the fourth, fifth, and sixth floors, the elevator lobbies are connected by a Public Corridor at the east side of the building. Basement elevator lobbies are also connected by a double-loaded corridor at the east side of the building; a parallel corridor extends from the Chestnut Street Elevator Lobby to a stair tower located near the middle of the west side.

Two main stair towers that serve all floors are located to the west of the main elevator lobbies at each end of the building. Finishes at these stairs between the first and second floors consist of marble treads and risers, marble-clad walls, anodized aluminum handrails, plaster ceilings with aluminum leaf, and ceiling-mounted white metal and glass incandescent light fixtures. Between the second and sixth floors, the wall and ceiling finishes are painted plaster. At the landing between the second and third floors, the stair finishes include precast terrazzo treads and landings, painted metal risers and stringers, and marble bases. The undersides of the stairs are finished with plaster soffits.

At the east side of the building, there is another centrally located original stair which connects the second through sixth floors. A secondary stair at the west side of the building runs from the fourth-floor Mechanical Equipment Room to the Basement. Adjacent to this stair, an additional egress stair was introduced between the first and second floors. Other stair assemblies include connections between the Post Office Work Room and the first-floor Mezzanine, stairs running between the Post Office Work Room and Basement, and several sets of stairs located to the rear (east) of the Courtrooms which connect the Private Corridors at the second and third floors.

There is a freight elevator at the Market Street (north) side of the building which serves the basement through sixth floors. A second freight elevator, which serves the basement through first floor, is located between the Post Office Work Room and the rear Loading Dock.


At the north and south ends of the building, above the elevator banks, there are two rooftop penthouses which serve as machine rooms for the elevators. The exterior walls of the penthouses are typically clad in limestone and brick. Interior finishes include acoustical wall tiles and concrete floors.

The building envelope includes multiple roof levels, all of which typically feature a modified bitumen roofing system with a combination of copper and foil-faced bituminous flashings.

(Adapted from the Historic Structure Report compiled by John Milner Associates, Inc., October 1989.)

The Robert N. C. Nix, Sr. Federal Building and Post Office is significant as a representative example of a relatively large, federally-funded, Depression-era project. Built under the auspices of the Public Works Administration (PWA), the building displays the stylistic approach of much late-1930s PWA architecture. A product of the locally prominent architect Harry Sternfeld (1888-1976) in association with the Ballinger Company (fl. 1920-present), it is one of a small number of high quality Art Deco buildings constructed in Philadelphia. Buildings of comparable style and quality in the Philadelphia area include the Main Branch of the United States Post Office (Thirtieth and Market Streets), the United States Custom House (Second and Chestnut Streets), and Central High School (Ogontz and Olney Avenues), all of which are PWA projects.

The PWA was created as part of the 1933 National Industrial Recovery Act and was organized to assist in easing the financial devastation brought on by the Depression. Its goals were to provide jobs, stimulate business, increase the national purchasing power, and fulfill the needs of the country for permanent and useful public services. Under the direction of Secretary of the Interior Harold L. Ickes, the PWA provided loans and grants for the construction of over 34,000 civil engineering and architectural projects by the conclusion of its programs in 1939.

Overt stylistic direction was not an acknowledged component of the PWA, but frequent use of Art Deco vocabulary often led to public and professional criticism of the apparently inevitable choice of “PWA Modern” for its projects. Although fundamentally traditional in their approach to construction and arrangement of interior spaces, Art Deco buildings employed a decorative vocabulary that emphasized expression of volume rather than surface decoration, simplicity of form, unbroken line, purity of color, strong contrast between light and shadow, expressive use of construction materials, and retention of stylized architectural elements derived from Classical forms. Such an approach provided an intentionally strong contrast to the more traditional, predominately Classically derived styles found in public works of the previous generation.

The architectural design of the Robert N. C. Nix, Sr. Federal Building and Post Office is also reliant on the use of a new technology, central air conditioning, in response to site-specific and program-specific circumstances. The application of this technology allowed for a traditional relationship of public and private spaces within courtrooms and adjacent areas in the context of a non-traditional urban through-block site. The use of air conditioning permitted the creation of architecturally distinguished and acoustically isolated public spaces by placing seven courtrooms and a law library at the center of the second and third floors. This approach retained the use of parallel public and private corridors, a circulation pattern typical of courthouse design and one that the architects, Harry Sternfeld in association with the Ballinger Company, were able to accommodate within the building’s linear configuration.

Harry Sternfeld was highly regarded within his profession as both a practicing architect and as an educator. He received his Bachelor of Science and Masters’ degrees in architecture from the University of Pennsylvania in 1911 and 1914, respectively. As a student, he received the Beaux-Arts Institute’s Paris Prize Scholarship, the most prestigious award available at the time for architecture students. The outbreak of World War I prevented Sternfeld from traveling to Paris and attending the École des Beaux-Arts until 1919. During the war, Sternfeld joined the faculty of Carnegie Institute of Technology, currently Carnegie-Mellon University, in Pittsburgh. Following his year at the École des Beaux-Arts, Sternfeld studied in Rome as a visiting fellow at the American Academy. Upon returning to the United States, he resumed teaching. In 1923, he joined the University of Pennsylvania as a Professor of Design. Major commissions executed by Sternfeld include the United States Post Office in Milton, Pennsylvania; the United States War Memorial at Audernarde, Belgium; and the Headquarters Building and War Department School at Fort Monmouth, New Jersey. Sternfeld associated with several architects at different points in his career, including George I. Bright, Edward H. Wigham, and the Ballinger Company.

The Ballinger Company was founded in 1920 by Walter Francis Ballinger following the end of an eighteen-year partnership with Emile G. Perrot. The firm has designed numerous buildings throughout the eastern United States and Canada, but is perhaps best known for its innovative designs for factories and other industrial buildings. The Ballinger Company is still active today.

The Robert N. C. Nix, Sr. Federal Building and Post Office also includes fine examples of the type of sculpture commissioned by the Treasury Department’s Section of Painting and Sculpture (known later as the Section of Fine Arts) during its most prolific period. Established in 1934, the Department’s programs were intended to assist emerging painters and sculptors and to encourage public interest in the arts. As with PWA-funded architecture, these programs also frequently appeared to promote the progressive styles deemed appropriate for their projects. Sculpture from this period is often typified by large, simple forms devoid of large amounts of detail. Sculptural panels by Donald De Lue and Edmond Amateis of idealized, heroic figures are excellent examples of the type of work produced under government programs during this period.

DeLue and Amateis achieved national prominence as artists during their careers. Donald DeLue was educated at the Boston Museum of Fine Arts School. The sculpture he designed for the Philadelphia Federal Building and Post Office constituted his first major public work, and one of his first commissions. Other important commissions included “The Rocket Thrower” for the 1964 New York World’s Fair; the Mississippi and Louisiana Memorials at Gettysburg, Pennsylvania; and “The Spirit of American Youth,” the Omaha Beach Figure at the United States Military Cemetery in Normandy, France. Edmond Amateis was born in Rome and was educated at the Beaux-Arts Institute of Design and the Académie Julienne. He served as fellow at the American Academy in Rome from 1921 to 1924, and in 1929 received the Henry O. Avery Prize from the Architectural League in New York. In 1933, he received the James E. McClease Prize from the Pennsylvania Academy of the Fine Arts.

Description Architect
1937 1941 Original construction Ballinger Company & Harry Sternfeld
1962 1964 Additional Court Facilities (5th & 6th Floors) General Services Administration
1969 1972 Additional Court Facilities (3rd, 4th & 5th Floors) Alexander Ewing & Associates
1979 1980 General Renovations General Services Administration
1983 1984 National Archives Branch Office (1st Floor) General Services Administration
1990 1997 Repairs and Alterations (Phases I - III) Bower Lewis Thrower Architects
1995 1996 National Archives Expansion General Services Administration
2001 2002 Facade Restoration Kelly/Maiello Inc.
2003 2005 Historic Door Repair & Restoration John Milner Architects, Inc.
2004 2006 Upgrades for U.S. District Court: Partial Renovation of 2nd & 5th Floors PSA-Dewberry
2004 2006 Upgrades for U.S. Marshal's Office: 5th Floor Suite Renovation PSA-Dewberry
2005 2006 Courtroom No. 1 - Plaster Wall Remediation/ Renovation and Related Work PSA-Dewberry
Last Reviewed: 2017-08-13