Oregon (ⁱ/ˈɔrɨɡən/ ORR-ə-gən) is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with Washington to the north, California to the south, Nevada on the southeast and Idaho to the east. The Columbia and Snake rivers delineate much of Oregon's northern and eastern boundaries, respectively. The area was inhabited by many indigenous tribes before the arrival of traders, explorers, and settlers who formed an autonomous government in Oregon Country in 1843. The Oregon Territory was created in 1848, and Oregon became the 33rd state on February 14, 1859.

Oregon is the 9th most extensive and the 27th most populous of the 50 United States. Salem is the state's capital and third-most-populous city; Portland is the most populous. Portland is the 29th-largest U.S. city, with a population of 583,776 (2010 US Census) and a metro population of 2,241,841 (2009 estimate), the 23rd-largest U.S. metro area. The valley of the Willamette River in western Oregon is the state's most densely populated area and is home to eight of the ten most populous cities.

This is a list of U.S. state capitol buildings in the United States and is not to be confused with a list of state capitals, which are the cities where these buildings are located.

A capitol typically contains the meeting place for its state's legislature and offices for the state's governor, though this is not true for every state. The Arizona State Capitol is now strictly a museum, and the legislature and the governor's office are in nearby buildings. The legislatures of Alabama, Nevada and North Carolina also meet in other nearby buildings, but their governor's offices remain in the capitol. Only Arizona does not have its governor's office in the state capitol, though in Delaware, Ohio, Michigan, Vermont & Virginia, the office there is for ceremonial use only.

Most States (39 of the 50) have facilities named "State Capitol". Indiana and Ohio use the term "Statehouse" and eight states use "State House": Maine, Maryland, Massachusetts, New Hampshire, New Jersey, Rhode Island, South Carolina, and Vermont. Delaware has a "Legislative Hall". The State of Alabama has a State Capitol, but the Legislature has since 1985 met in the State House.

The Oregon State Capitol is the building housing the state legislature and the offices of the governor, secretary of state, and treasurer of the U.S. state of Oregon. It is located in the state capital, Salem. The current building, constructed from 1936 to 1938, and expanded in 1977, is the third to house the Oregon state government in Salem. Two former capitol buildings were destroyed by fire, one in 1855 and the other in 1935.

New York architects Trowbridge & Livingston conceived the current structure's Art Deco design, in association with Francis Keally. Much of the interior and exterior is made of marble. The Oregon State Capitol was placed on the National Register of Historic Places in 1988.

The Public Works Administration, part of the U.S. government, 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 166 feet (51 m). The wings, which doubled the floor space of the building to about 233,750 square feet (21,716 m²), 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).