The Oregon Territory was home to many Native American tribes including the Bannock, Chasta, Chinook, Kalapuya, Klamath, Molalla, Nez Perce, Takelma, and Umpqua when the Lewis and Clark Expedition travelled through in 1805. There they stopped for the winter and built Fort Clatsop near the Columbia River in Oregon.
In 1811, Great Britain and the Northwest Company claimed the territory through their trappers and tradesmen in the area. In the War of 1812, the British gained control of all of the Pacific Fur Company posts but the Treaty of 1818 established joint British and American occupancy of the region west of the Rocky Mountains to the Pacific Ocean. By the 1820s and 1830s, the Hudson’s Bay Company dominated the Pacific Northwest from its Columbia District headquarters at Fort Vancouver in Oregon. The British and Americans both claimed the Oregon territory for some time to come.
The Oregon Territory was created in 1848 after American settlement began in earnest in the 1840s. The famous Oregon Trail brought many new American settlers to Oregon Country and eventually the British ceded rights to the United States government to claim Oregon as an official territory of the U.S. and the border between the United States and British North America was then set at the 49th parallel.
Oregon became the 33rd state to join the Union of the United States of America on February 14, 1859.