An Overview: Oregon Treaty:

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 as the State of Oregon.

Origin
Originally claimed by several countries (see Oregon Country), the region was divided between the UK and the US in 1846. When established, the territory encompassed an area that included the current states of Oregon, Washington, and Idaho, as well as parts of Wyoming and Montana.

The capital of the territory was first Oregon City, then Salem, followed briefly by Corvallis, then back to Salem, which became the state capital upon Oregon's admission to the Union.

Also read: The United States decided to divide Oregon Territory with who and why? 

Aftermath

The Oregon Treaty is a treaty between the United Kingdom and the United States that was signed on June 15, 1846, in Washington, D.C. The treaty brought an end to the Oregon boundary dispute by settling competing for American and British claims to the Oregon Country; the area had been jointly occupied by both Britain and the U.S. since the Treaty of 1818.

The Treaty of 1818 set the boundary between the United States and British North America along the 49th parallel of north latitude from Minnesota to the 'Stony Mountains' (now known as the Rocky Mountains).

The region west of those mountains was known to the Americans as the Oregon Country and to the British as the Columbia Department or Columbia District of the Hudson's Bay Company. (Also included in the region was the southern portion of another fur district, New Caledonia.)

The treaty provided for joint control of that land for ten years. Both countries could claim land and both were guaranteed free navigation throughout.

Also read: What is The Treaty of Versailles?