The 49th parallel north is a circle of latitude that is 49 degrees north of the Earth's equatorial plane. It crosses Europe, Asia, the Pacific Ocean, North America, and the Atlantic Ocean.The parallel forms part of the United States- Canadian Border from British Columbia to Manitoba on the Canadian side and from Washington to Minnesota on the U.S. side, or from the Strait of Georgia to the Lake of the Woods. Its use as the international border is a result of the Anglo-American Convention of 1818 and the Oregon Treaty of 1846.