The Oregon territory was contested between the United States and what other country

Oregon originally claimed by theGreat Britain, France, Russia, and Spain. Spanish claims were later taken over by the US. The land area of the region that was claimed was unclear. In 1846, the boundary between America and the British territory was formally set at 49 parallels. The agreement between British North America and the US was signed on June 15, 1846 in Washington. The signing of this treaty prevented the third war in 70 years. The British part was north of paralel and the entire Vancouver island. The British part later came to Canada, while the territory south of 49 parallels came to America. Oregon was officially accepted into the Union of States on February 14, 1859.

The righ answer is: The Oregon territory was contested between United States and British North America.