The most outstanding features of Holabird and Root and Ellerbe and Company's design for the new Saint Paul City Hall were an efficient and practical plan, the incorporation of technologically advanced functional features, and the expression of these modern functional concerns in the non-traditional Art Deco style. Primary considerations for the structure, as set forth by the Advisory Commission, were accommodating "the practical necessities", and " clothing those necessities with a simple but dignified exterior". Using information gathered in an analysis of the spatial needs of city and county offices, Holabird and Root devised a plan in which offices that dealt heavily with the public were located on the main floor of the building, and other related departments were grouped on upper floors. The Holabird and Root design also made possible highly efficient use of space. Over 70% of the interior is usable work space, compared to 30% usable space in the Minnesota State Capitol building.
Specific functional features of the City Hall also suggest its designers' interest in constructing a building that was "modern" in its time. Elevators in the building were the most modern and speedy available in 1930. All clocks were originally controlled from a masterboard in a "penthouse" that also held a 60-gallon dispenser which automatically filled all restroom soap glasses. Features such as these not only gave the City Hall building a distinctively modern image In the 1930's, but also allow it to continue to be used in its original capacity without major alterations.
The concern for modernity suggested by functional features of the Saint Paul City Hall is clearly expressed in the stylistic appearance of the building. Holabird and Root and Ellerbe and Company's design disregards the classical motifs of the Beaux Arts style, using instead an American Art Deco style called "American Perpendicular". In contrast to the eclecticism characteristic of earlier architecture, the American Perpendicular style was considered futuristic in the 1920's and 1930's. This new style can be traced to the work of Finnish architect Eliel Saarinen. In 1922, Saarinen entered the Chicago Tribune Competition with a design for a "styleless" skyscraper composed of severe geometric massing and sharp setbacks. Saarinen's design, though not chosen, was highly regarded and led to a new appreciation for noneclectic, modern skyscraper architecture.
The exterior of the Saint Paul City Hall reflects the American Perpendicular style which evolved from designs like that of Saarinen. The structure is a symmetrical massing of severe geometric forms of smooth-faced, coursed Indiana limestone, sparsely decorated with low flat reliefs of the same material. A three-story base with setbacks surrounds a central twenty-story tower which has further setbacks at its top. The three-story base and tower have vertically aligned rows of windows linked between stories by plain, flat, black spandrels. Flat vertical courses of limestone separate the bays. These alternating strips of dark windows and spandrels, and lighter tone limestone give the structure a dramatic, soaring appearance.
The primary entrances to City Hall on Third and Fourth Streets are decorative focal points on the exterior of the structure. The Fourth Street entrance is a three story block recessed between graduated one and two-story projections, all placed symmetrically in front of the twenty-story tower. A row of five glass doors and surmounting decoration are framed within the setbacks by two shallow three-story limestone projections. The placement of the doors within the recess and between these graduated flanking masses creates a ceremonial-like transition from the urban street into the interior of the City Hall building.
Above the doors of the Fourth Street entrance is a panel identifying the structure as the "Saint Paul City Hall and Ramsey County Courthouse", and a relief by sculptor Lee Lawrie, who also made sculptures for the Nebraska State Capitol, the RCA Building, and other buildings in Rockefeller Center. Both the style and content of Lawrie's relief express the progressive Ideals of the city and county that are also implied by the stripped down, modern appearance of the City Hall building itself. For the Fourth Street entrance, Lawrie has used a hard-edged flat relief style to schematically portray a group of figures at a street crossing. Lawrie's animated treatment of the scene, and his inclusion of a variety of figures indicate his perception of the dynamic quality of urban life, and the diversity within the urban populus. Images of a policeman directing traffic, workers carrying axes, a mail carrier, and a newspaper boy convey the importance of labor in the 1930's. A traffic light, an automobile, and a fire hydrant are also included to indicate the benefits of modern technology to the urban dweller. Above the street crossing relief, a tall narrow window flanked by vertical flutes runs up to a relief of a monumental female figure symbolizing "Liberty". Though carved in the same "modern", angular, geometric style as the figures in the street crossing scene, the figure's formal frontal pose,crown, and open book with the inscriptions, "VOX POPULI" and "JUS CIVILE" reflect ties to the traditional imagery for government ideals.
The lower three-story masses to the sides of the Fourth Street entrance also have limestone relief decorations which continue around the building at street level. Fretwork ornaments the top edges of the one-story projections, and a series of three small reliefs of city, county, and state emblems is repeated around the entire building below the fretwork. The City of Saint Paul is represented by a crown and Roman sword; Ramsey County is represented by a depiction of the washstand on which Governor Ramsey wrote the territorial proclamation, and the scroll of proclamation; the state of Minnesota is represented by an eight pointed image of the North Star.
The other main entrance to the Saint Paul City Hall is located on the opposite side of the building on Third Street. The Third Street entrance is a three-story limestone proscenium-like projection from the main twenty story tower. A row of five glass doors is set into the projection and surmounted by a silver glazed glass screen in the form of three large flutes. Two limestone reliefs by Lee Lawrle flank the doors of the entrance. Much like the Fourth Street reliefs, the imagery and style of the reliefs of the Third Street entrance reflect both the ideals of a modern industrial society, and institutional ties to more traditional, abstract government ideals.
In the left relief, civic government is symbolized by a goddess figure wearing a mural crown (the emblem of civic society) and holding a staff with two entwined serpents in her right hand. In her left hand she holds balanced scales with the inscription, "LAW AND ORDER". Images of "modern" urban ideals surrounding the goddess are an open book, a nail keg, and cogged wheels inscribed respectively, "EDUCATION", "COMMERCE", AND "INDUSTRY". A panoramic view of the city of Saint Paul, including the new City Hall building, is depicted behind the goddess.
The pendant relief panel to the right of the Third Street entrance symbolizes rural life In Ramsey County. A female figure holding a scythe over a bundle of wheat inscribed "AGRICULTURE", and a cornucopia inscribed "ABUNDANCE" is set in front of a schematized landscape of pine trees, mountains, and a rising sun. Also included is a train with the banner, "TRANSPORTATION", presumably symbolizing ties between city and country made possible by modern technology. Outside the doorway projection on the wall surface of the main tower are two additional relief panels. A sculpture of a calumet on the right symbolizes peace, and balanced scales on the left represent justice.