The federal government's Public Works Administration partially financed construction which was completed during the Great Depression in 1938. The building was erected at a cost of $2.5 million for the central portion of the building, which includes a dome of . The wings, which doubled the floor space of the building to about , were added later for $12.5 million. The grounds outside the capitol building contain artwork, fountains, and flora, including the state tree (Douglas fir) and state flower (Oregon grape).