Oregon is a state in the Pacific Northwest region of the United States. The area was inhabited by many indigenous tribes before the arrival of traders, explorers and settlers. The Oregon Territory was created in 1848 after American settlement began in earnest in the 1840s. Oregon became a state (33rd) on February 14, 1859. Oregon is located on the Pacific coast between 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. Salem is the state's third most populous city and the state capital, with Portland the most populous. Portland is currently the 30th largest U.S. city with a population of 575,930 (2008 estimate) and a metro population of 2,175,133 (2007 estimate), 23rd largest U.S. metro area.