Oregon boundary dispute

The Oregon boundary dispute or the Oregon Question was a 19th-century territorial dispute over the political division of the Pacific Northwest of North America between several nations that had competing territorial and commercial aspirations in the region.

Expansionist competition into the region began in the 18th century, with participants including the Russian Empire, Great Britain, Spain, and the United States. After the War of 1812, the Oregon dispute took on increased importance for diplomatic relations between the British Empire and the fledgling American republic. In the mid-1820s, the Russians signed the Russo-American Treaty of 1824 and the Russo-British Treaty of 1825, and the Spanish signed the Adams–Onís Treaty of 1819, by which Russia and Spain formally withdrew their respective territorial claims in the region, and the British and the Americans acquired residual territorial rights in the disputed area.^[1] But the question of sovereignty over a portion of the North American Pacific coast was still contested between the United Kingdom and the United States. The disputed area was defined as the region west of the Continental Divide of the Americas, north of Mexico's Alta California border of 42nd parallel north, and south of Russian America at parallel 54°40′ north. The British generally called this region the Columbia District and the Americans generally called it Oregon Country.

During the 1844 United States presidential election campaign, the Democratic Party proposed ending the Oregon Question by annexing the entire area. The U.S. Whig Party, in contrast, evinced no interest in the question – due, some scholars have claimed, to the Whig view that it was unimportant compared to other domestic problems.^[2] The Democratic candidate, James K. Polk, invoked the popular theme of manifest destiny and appealed to voters' expansionist sentiments in pressing for annexation, and defeated the Whig candidate, Henry Clay. Polk then sent the British government an offer to agree on a partition along the 49th parallel (which had been previously offered). However, the resulting negotiations soon faltered: the British still pressed for a border along the Columbia River. Tensions grew as American expansionists, such as Senator Edward A. Hannegan of Indiana and Representative Leonard Henly Sims of Missouri, urged Polk to annex the entire Pacific Northwest all the way to the 54°40′ parallel north (which is what the Democrats had called for during the presidential campaign). These tensions gave rise to slogans such as "Fifty-four Forty or Fight!" At the same time, U.S. relations with Mexico were rapidly deteriorating as a result of the recent U.S. annexation of Texas. This gave rise to a concern that the U.S. might have to fight two wars on two fronts at the same time. Thus, just before the outbreak of the Mexican–American War, Polk retreated to his earlier position, calling for the Oregon border to run along the 49th parallel.

The 1846 Oregon Treaty established the border between British North America and the United States along the 49th parallel until the Strait of Georgia, where the marine boundary curved south to exclude Vancouver Island and the Gulf Islands from the United States. As a result, a small portion of the Tsawwassen Peninsula, Point Roberts, became an exclave of the United States. Vague wording in the treaty left the ownership of the San Juan Islands in doubt, as the division was to follow "through the middle of the said channel"^[3] to the Strait of Juan de Fuca. During the so-called Pig War, both nations agreed to a joint military occupation of the islands. Kaiser Wilhelm I of the German Empire was selected as an arbitrator to end the dispute, with a three-man commission ruling in favor of the United States in 1872. There the Haro Strait became the border line, rather than the British-favored Rosario Strait. The border established by the Oregon Treaty and finalized by the arbitration in 1872 remains the boundary between the United States and Canada in the Pacific Northwest.