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The Convention of 1818 is a bilateral agreement between the United States and British North America (later Canada), which resolved territory disputes between the two nations setting the boundary at the forty-ninth parallel of latitude. It was the only territory cession the U.S. made to the United Kingdom and, at the same time, was the beginning of their cooperation.

Explanation:

The Convention of 1818 is also known as the Treaty of Joint Occupation, Anglo-American Convention of 1818, or Treaty of 1818.  It was negotiated and signed on the 20th of October 1818, in London, by Henry Goulburn, an undersecretary of state, and Frederick John Robinson, Treasurer of the Royal Navy for the U.K. For the U.S. party it was signed by Richard Rush, minister to the U.K. and by Albert Gallatin, ambassador to France. The treaty came into effect on the 30th of January 1819 and consisted of six articles.

Article I discussed the privileges for the US fishermen and secured fishing rights for the US on the territory off the shores of Newfoundland and Labrador islands. Article II sets the boundary between the U.S. territories and British North America from the most North Western point of Lake of Woods to the Stony (Rocky) Mountains.

Article III provided both nations with the joint right to territories in the North West Coast of America, Westward of the Stony Mountains (Oregon) for a period of ten years. Article IV extended existing commerce regulations between the United States and Canada for another ten years. According to Article V, any differences over territories, places, or possessions between the two nations were to be referred to a foreign mediator. Article VI secured the mutual ratification of the treaty within the six-month period.

In the wake of the war of 1812, the Convention of 1818, along with the Rush-Bagot Pact of 1817, served as a valve to release tensions between the U.S. and British North America. The treaty did not manage to solve all the territory disputes standing between the two nations completely.

However, the differences that emerged as a result of the Treaty of Paris of 1783, which ended the American Revolutionary War, that produced for the U.S. most of the territory east of the Mississippi River, and made Britain recognize the sovereignty of the United States, were resolved.  The Convention of 1818 marked a significant turning point in the relationship between British North America and former British colonies starting their cooperation.

Under the agreement, Britain ceded the south of Rupert’s Land of the 49th parallel and east of the Continental Divide, including the Red River Colony south of that latitude, while the United States ceded the northernmost edge of the Missouri Territory north of the 49th parallel. The agreement determined the change of the map of the disputed lands involving the 49th parallel, mostly due to the practical reasoning.

The straight line of the parallel allowed for a much easier survey of the territories compared to the previous boundaries made along the watersheds. Specifically, as the Pacific Coast area in dispute was dominated by the British owned Hudson’s Bay Company, the agreement restrained both parties from seeking unfair advantage of the area. However, in the next two decades that followed the ratification of the Treaty of 1818, the U.S. fur traders continued the encroachment of the said territories, which caused a resumption of negotiations of the territory and commercial matters.