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 (255,000 km²), Oregon is the ninth largest and, with a population of 4 million, 27th most populous U.S. state. The state capital, Salem, is the second most populous of its cities, with 164,549 residents. while Portland, with 632,309 residents, is the most populous, ranking as the 26th most populous city in the United States. Portland's metro population of 2,389,228 ranks the 23rd largest metro in the nation.