Why is the ninth month called September?
1765 as the name of a large river in the west of North America, probably the modern Columbia; of uncertain and disputed origin. It seems to be of Algonquian origin. From 1848 as the name of a U.S. territory (admitted as a state 1859).
State in the northwestern United States bordered by Washington to the north, Idaho to the east, Nevada and California to the south, and the Pacific Ocean to the west. Its capital is Salem, and its largest city is Portland.
Note: Before the coming of the railroads, the Oregon Trail was used as an overland emigration route from the Missouri River to the Columbia River country (all of which was then called Oregon).