Pioneer Courthouse is a federal courthouse in Portland. Construction began in 1869, and it is the oldest federal building in the Pacific Northwest and the second-oldest west of the Mississippi River. It was built in stages between 1869 and 1903. Judge Matthew Deady first used it in 1875, when it was called the United States Building.
People also call it the Pioneer Post Office, because a popular downtown post office was inside until 2005. It was added to the National Register of Historic Places in 1973 and became a National Historic Landmark in 1977.
It has survived several attempts to demolish it. In March 1933 city engineer Olaf Laurgaard proposed tearing it down for a parking garage. Architect A. E. Doyle and other local groups sharply opposed the idea, and the building stayed. Today it is one of four main places where the Ninth Circuit Court of Appeals hears oral arguments.