The capital and the Capitol in Salem
Salem has been Oregon's capital since statehood in 1859. The building on the hill is the third capitol on the site's story.
The building
Wikipedia reports that the first capitol burned on December 29, 1855, and the second on April 25, 1935. The third was completed on June 18, 1938, and dedicated on October 1, 1938. It was designed by the New York firm Trowbridge and Livingston with Francis Keally, with an exterior of Vermont marble. Four murals in the rotunda show Robert Gray's 1792 Columbia River exploration, the Lewis and Clark Expedition and two covered-wagon scenes. A 1977 expansion added wings with legislative offices, hearing rooms and underground parking.
Visiting
The Capitol is at 900 Court Street NE. Its visitor site lists building, educational and tower tours, a virtual tour and a Capitol Store. It gives no regular hours on its home page, so check the site for tour times before you go. Public legislative hearings are listed on the Oregon Legislature's calendar.