The Territory of Oregon was an organized incorporated territory of the United States that existed from August 14, 1848, until February 14, 1859, when the southwestern portion of the territory was admitted to the Union

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 as the State of Oregon. Originally claimed by several countries (See Oregon Country

Oregon Country

The Oregon Country was a predominantly American term referring to a disputed ownership region of the Pacific Northwest of North America. The region was occupied by British and French Canadian fur traders from before 1810, and American settlers from the mid-1830s, with its coastal areas north from...

), the region was divided between the U.S. and Great Britain in 1846. When established, the territory encompassed an area that included the current states of Oregon, Washington, and Idaho

Idaho

Idaho is a state in the Rocky Mountain area of the United States. The state's largest city and capital is Boise. Residents are called "Idahoans". Idaho was admitted to the Union on July 3, 1890, as the 43rd state....

, as well as parts of Wyoming

Wyoming

Wyoming is a state in the mountain region of the Western United States. The western two thirds of the state is covered mostly with the mountain ranges and rangelands in the foothills of the Eastern Rocky Mountains, while the eastern third of the state is high elevation prairie known as the High...

 and Montana

Montana

Montana is a state in the Western United States. The western third of Montana contains numerous mountain ranges. Smaller, "island ranges" are found in the central third of the state, for a total of 77 named ranges of the Rocky Mountains. This geographical fact is reflected in the state's name,...

.