Pioneer Courthouse, originally designed by Alfred B. Mullett, Supervising Architect of the Treasury, is the oldest surviving federal structure in the Pacific Northwest and the second oldest courthouse west of the Mississippi. First completed in 1875 with two west wings added in 1905, the courthouse was originally designed as a Federal Courthouse, customs house and post office. For the last 35 years, Pioneer Courthouse has been home to the U.S. Court of Appeals. In 1996 the General Services Administration made a commitment to embark on the modernization of Pioneer Courthouse while restoring and preserving this National Historic Landmark.
The complete renovation of Pioneer Courthouse included architectural, mechanical, electrical and communication systems, as well as numerous site improvements. A major seismic upgrade was performed to structurally isolate the courthouse by using ground-base isolators. Due to this innovative seismic technology, virtually no reconstruction was needed. The primary goal of the rehabilitation was to restore and maintain the bold and elegant design of the original building. Extensive time was spent assessing the existing structure through archaeological, geological and structural investigations. Historic photographs from the Oregon Historical Society archives and early construction photos from the GSA archives were studied. The renovation design maintains the character of the 130 year old building and incorporates details which are historically accurate, or where appropriate, historically compatible. Integrated into the historic fabric is the infrastructure for a building that is up to date with current technology to meet the needs of a Federal Appellate Judicial Court.