One Pacific Square, Office building in Old Town, Portland, US

One Pacific Square, also known as the Northwest Natural Gas Building, is a 13-story glass-clad tower at 220 Northwest 2nd Avenue in Portland, Oregon. Completed in 1983, it has an eight-sided, crystal-shaped plan with upper floors set at a 45-degree angle. It occupies a full block bounded by Davis, Everett, First and Second streets and contains 230,000 square feet of space.

Planning began in 1974 and construction started in July 1981 on the $23-million project, designed by architect Richard A. Campbell for developer Hayden Corp. A dedication ceremony on April 8, 1982 buried a time capsule, and the building topped out that June. One Pacific opened on April 1, 1983, with NW Natural leasing about 55 percent of the space and using it as headquarters for roughly 30 years until moving to 250 Taylor in 2020.

Bart King's An Architectural Guidebook to Portland records the nickname "R2D2 Building", after the Star Wars droid. The comparison comes from the tower's eight-sided, crystal-shaped plan, whose upper floors are set at a 45-degree angle rather than forming a cylinder.

The tower occupies the full block bounded by Northwest Davis, Everett, First and Second, so it can be circled on foot from any side. Its entrance is at 220 Northwest 2nd Avenue, in the block just north of the Old Town core. The eight-sided plan means the upper floors sit at a 45-degree angle to the street grid.

The tower was planned as one of four similar high-rises, with the others intended at 20, 27 and 28 stories; only this 13-story building was realized. A time capsule was buried at the dedication ceremony on April 8, 1982, before the building topped out that June.