Oregon was inhabited by many indigenous tribes before Western traders, explorers, and settlers arrived. An autonomous government was formed in the Oregon Country in 1843 before the Oregon Territory was created in 1848. Oregon became the 33rd state on February 14, 1859. Today, at 98,000 square miles (250,000 km2), Oregon is the ninth largest and, with a population of 4 million, 27th most populous U.S. state. The capital, Salem, is the second most populous city in Oregon, with 164,549 residents. Portland, with 632,309 residents, is the most populous and ranks as the 26th most populous city in the United States. The Portland metropolitan area, which also includes the city of Vancouver, Washington, to the north, ranks the 23rd largest metro area in the nation, with a population of 2,389,228.