This Week in History


The 49th Parallel

This story was originally published in 2002

On June 15, 1846, Great Britain and the United States signed the Oregon Treaty, avoiding war and establishing the present-day southern boundary of British Columbia, now part of the world's longest undefended border.

Canada in 1825

Canada in 1825
© Canadian Geographic

The Oregon Territory comprised what are now Oregon, Washington, Idaho, parts of Montana and Wyoming, and most of British Columbia. The territory's coastline attracted ocean-going fur traders late in the 1700s. Spain, Mexico, Britain, the U.S., and even Russia made claims along this coast. By 1845, however, only Britain and the U.S. sought control of the river mouth and the fertile lands around the Columbia River.

In 1818, Britain and the U.S. agreed to share the territory for 10 years. In 1825, the Hudson's Bay Company (HBC) proposed a boundary settlement that would leave its people the rich fur reserves north of the Columbia River. The Americans refused. The boundary east of the Rocky Mountains was already set at the 49th parallel, and they wanted it extended west to the Pacific. Britain rejected this, so joint occupancy was reaffirmed for an indefinite period in 1827.

In the 1840s, the number of American settlers in the territory increased dramatically, and they demanded the end of joint occupation. By 1843, they had established a provisional government with hopes of establishing a legitimate one in the future. By contrast, the HBC was not encouraging European settlement, and its monopoly could not withstand the American settlers and free traders. Neither side considered the many Aboriginal nations that also lived there.

The Rocky Mountains from the Columbia River

The Rocky Mountains from the Columbia River
© LAC / 1969-4-26

In 1844, President James Polk sought to increase U.S. territory because he believed in American "manifest destiny" - the principle that Americans had the right to settle anywhere in North America. Consequently, many Americans claimed the entire Oregon Territory to Alaska's southern boundary, 54°40' north latitude, denying Britain access to the Pacific Coast. "54-40 or fight" became their slogan and both countries prepared for war. Polk, however, decided to compromise and Britain was ready to negotiate. HBC Governor George Simpson had already relocated the main shipping depot to Fort Victoria, and British officials in London had abandoned the idea of the Columbia River becoming "the St. Lawrence of the West."

The Oregon Treaty of 1846, an event of national historic significance, continues the 49th parallel as the boundary to salt water. The U.S. retained everything south of this line and Britain retained everything north of the line and all of Vancouver Island.

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