The 49th parallel is a circle of latitude that is 49 degrees north of the Earth's equatorial plane. It serves as a significant boundary between the United States and Canada, stretching from the Pacific Ocean in the west to the Atlantic Ocean in the east. This line was established as part of the Oregon Treaty in 1846, which resolved territorial disputes between the two countries. The 49th parallel is notable for its relatively straight line across diverse landscapes, including mountains, forests, and plains. It passes through several U.S. states, such as Washington and Montana, as well as Canadian provinces like British Columbia and Alberta. This latitude is often referenced in discussions about international borders and geography.