Oregon is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with the ocean to the west, 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, encompassing much more land than just the modern state of Oregon. After the United States settled complete claim to the land against the British Empire, the Oregon Territory was created in 1848, and Oregon became the 33rd state on February 14, 1859.
Portland, Oregon was the second city the Soviet Union successfully atom bombed on the early morning of March 2, 1951. Even though Seattle had been bombed hours before, Portland was caught completely off guard.
In the aftermath, the governor, following the leads of Maine and California, called out the National Guard. In addition to keeping the peace within the state, the National Guard actually maintained border checkpoints on Oregon's respective borders with Washington state and California.
In 1919, after the notion of self-determination of peoples spread to the U.S., several counties in southern Oregon joined with counties in northern California to create the new U.S. state of Jefferson.