The building features a four-story Corinthian colonnade at its eastern end (originally the principal façade) and makes extensive use of glazed terracotta.

An extension westward to Broadway was added in 1925, approximately doubling the building's size[6] such that it now occupies half a city block.

The firm purchased a quarter-block of land at the northwest corner of Sixth and Stark streets in early 1916 and hired Portland architect A. E. Doyle to design a new, dedicated headquarters building.

[24] At that time, it announced plans for another major expansion of its headquarters on property it had acquired diagonally across from the Wells Fargo Building.

[27] But the headline structure was the U.S. Bancorp Tower, a 42-story building that opened in 1983 (having already been part of the bank's long-term site plans in 1970,[27] but ultimately delayed until the 1980s).

[28] Notwithstanding this major expansion, the firm continued to own and use its landmark 1917 building, which company president LeRoy Staver, in a 1970 Oregonian article, called "a jewel of a banking property and one that will never be duplicated".

"[29] The U.S. National Bank of Oregon was honored by the Portland Historical Landmarks Commission in that year for its longstanding commitment to maintaining the building in nearly original condition.

[9][31] The building is five stories tall including a mezzanine level and, after its 1925 expansion, occupies a 100-by-200-foot (30 m × 61 m) area, along the north side of SW Stark Street from Sixth Avenue to Broadway.

The central entrance features a pair of large bronze doors with highly decorated bas relief panels, surrounded by detailed terracotta, including replicas of early Greek, Roman and U.S. coins[33] in the decoration framing the door, and a heraldic eagle in a pedimented cornice above the doorway.

The overall exterior design was modeled closely on a 1904 bank building, the headquarters of the Knickerbocker Trust Company, in New York City.

Square columns of polished marble topped by Corinthian capitals that incorporate an eagle motif line all four sides of the main public space.

A remodeling of the fourth-floor offices in 1948, based on designs by Pietro Belluschi, incorporated Oregon myrtle in the paneling and custom furnishings.

The bank's board room, located on the third floor, includes a marble fireplace and stained glass windows by the noted Portland company, Povey Brothers Studio.

Ornamental lighting fixtures with brass wall mountings adorn the east and west ends of the room, and a bronze ring chandelier hangs above the center.

MAX light rail trains have passed in front of the building's east end on 6th Avenue since 2009, following a 2007–08 rebuilding of the transit mall.