The Webster-Ashburton Treaty of 1842

How the Treaty Smoothed US-Canadian Relations

Sign along US – Canada border warns of Canadian immigration laws
Along the US-Canadian Border. Joe Raedle / Getty Images

A major achievement in diplomacy and foreign policy for post-revolutionary America, the Webster-Ashburton Treaty of 1842 peacefully eased tensions between the United States and Canada by resolving several long-standing border disputes and other issues.

Key Takeaways: Webster-Ashburton Treaty

  • The Webster-Ashburton Treaty of 1842 peacefully settled several long-standing issues and border disputes between the United States and Canada.
  • The Webster-Ashburton Treaty was negotiated in Washington, D.C., between U.S. Secretary of State Daniel Webster and British diplomat Lord Ashburton starting on April 4, 1842.
  • Key issues addressed by the Webster-Ashburton Treaty included the location of the U.S.-Canadian border, the status of American citizens involved in the Canadian rebellion of 1837, and the abolition of the international trade of enslaved people.
  • The Webster–Ashburton Treaty established the U.S.-Canadian border as drawn in the 1783 Treaty of Paris and the Treaty of 1818.
  • The Treaty provided that the United States and Canada would share the Great Lakes for commercial uses.
  • Both the United States and Canada further agreed that the international trade of enslaved people on the high seas should be banned. 

Background: The 1783 Treaty of Paris

In 1775, on the brink of the American Revolution, the 13 American colonies were still part of the 20 territories of the British Empire in North America, which included the territories that would become the Province of Canada in 1841, and eventually, the Dominion of Canada in 1867.

On September 3, 1783, in Paris, France, representatives of the United States of America and King George III of Great Britain signed the Treaty of Paris ending the American Revolution.

Along with acknowledging America’s independence from Britain, the Treaty of Paris created an official border between the American colonies and the remaining British territories in North America. The 1783 border ran through the center of the Great Lakes, then from Lake of the Woods “due west” to what was then believed to be the source or “headwaters” of the Mississippi River. The border as drawn gave the United States lands that had previously been reserved for Indigenous peoples of the Americas by earlier treaties and alliances with Great Britain. The treaty also granted Americans fishing rights off the coast of Newfoundland and access to the eastern banks of the Mississippi in return for restitution and compensation to British loyalists who had refused to take part in the American Revolution.

Differing interpretations of the 1783 Treaty of Paris resulted in several disputes between the United States and the Canadian colonies, most notably the Oregon Question and the Aroostook War.

The Oregon Question

The Oregon Question involved a dispute over territorial control and commercial use of the Pacific Northwest regions of North America between the United States, the Russian Empire, Great Britain, and Spain.

By 1825, Russia and Spain had withdrawn their claims to the region as a result of international treaties. The same treaties granted Britain and the United States residual territorial claims in the disputed region. Called the “Columbia District” by Britain and the “Oregon Country” by America, the contested area was defined as being: west of the Continental Divide, north of Alta California at the 42nd parallel, and south of Russian America at the 54th parallel.

Hostilities in the disputed area dated back to the War of 1812, fought between the United States and Great Britain over trade disputes, the forced service, or “impressment” of American sailors into the British Navy, and Britain’s support of Native American attacks on Americans in the Northwest frontier.

After the War of 1812, the Oregon Question played an increasingly important role in international diplomacy between the British Empire and the new American Republic.

The Aroostook War

More of an international incident than an actual war, the 1838-1839 Aroostook War – sometimes called the Pork and Beans War – involved a dispute between the United States and Britain over the location of the border between the British colony of New Brunswick and the U.S. state of Maine.

While no one was killed in the Aroostook War, Canadian officials in New Brunswick arrested some Americans in the disputed areas and the U.S. State of Maine called out its militia, which proceeded to seize parts of the territory.

Along with the lingering Oregon Question, the Aroostook War highlighted the need for a peaceful compromise on the border between the United States and Canada. That peaceful compromise would come from the Webster-Ashburton Treaty of 1842.

The Webster-Ashburton Treaty

From 1841 to 1843, during his first term as Secretary of State under President John Tyler, Daniel Webster faced several thorny foreign policy issues involving Great Britain. These included the Canadian border dispute, the involvement of American citizens in the Canadian rebellion of 1837, and the abolition of international trade of enslaved people.

On April 4, 1842, Secretary of State Webster sat down with British diplomat Lord Ashburton in Washington, D.C., both men intent on working things out peacefully. Webster and Ashburton started by reaching an agreement on the boundary between the United States and Canada.

The Webster–Ashburton Treaty re-established the border between Lake Superior and the Lake of the Woods, as originally defined in the Treaty of Paris in 1783. And confirmed the location of the border in the western frontier as running along the 49th parallel up to the Rocky Mountains, as defined in the Treaty of 1818. Webster and Ashburton also agreed that the U.S. and Canada would share the commercial use of the Great Lakes.

The Oregon Question, however, remained unresolved until June 15, 1846, when the U.S. and Canada averted a potential war by agreeing to the Oregon Treaty.

The Alexander McLeod Affair

Shortly after the end of the Canadian Rebellion of 1837, several Canadian participants fled to the United States. Along with some American adventurers, the group occupied a Canadian-owned island in the Niagara River and employed a U.S. ship, the Caroline; to bring them supplies. Canadian troops boarded the Caroline in a New York harbor, seized her cargo, killed one crewman in the process, and then allowed the empty ship to drift over Niagara Falls.

A few weeks later, a Canadian citizen named Alexander McLeod crossed the border into New York where he bragged that he had helped seize the Caroline and had, in fact, killed the crewman. American police arrested McLeod. The British government claimed that McLeod had acted under the command of British forces and should be released to their custody. The British warned that if the U.S. executed McLeod, they would declare war.

While the U.S. government agreed that McLeod should not face trial for actions he had committed while under orders of the British Government, it lacked the legal authority to force the State of New York to release him to British authorities. New York refused to release McLeod and tried him. Even though McLeod was acquitted, hard feelings remained.

As a result of the McLeod incident, the Webster-Ashburton Treaty agreed on principles of international law allowing for the exchange, or “extradition” of criminals.

International Trade of Enslaved People

While Secretary Webster and Lord Ashburton both agreed that the international trade of enslaved people on the high seas should be banned, Webster refused to Ashburton’s demands that the British be allowed to inspect U.S. ships suspected of carrying enslaved people. Instead, he agreed that the U.S. would station warships off the coast of Africa to search suspected ships flying the American flag. While this agreement became part of the Webster–Ashburton Treaty, the U.S. failed to vigorously enforce its ship inspections until the Civil War began in 1861.

The Case of the Ship Creole

Though it was not specifically mentioned in the treaty, Webster-Ashburton also brought a settlement to the enslavement-related case of the Creole.

In November 1841, the U.S. ship Creole was sailing from Richmond, Virginia, to New Orleans with 135 enslaved people on board. Along the way, 128 of those enslaved escaped their chains and took over the ship killing one of the White traders. As commanded by those enslaved, the Creole sailed to Nassau in the Bahamas where the enslaved people were set free.

The British government paid the United States $110,330 because under international law at the time officials in the Bahamas did not have the authority to free those enslaved. Also outside the Webster-Ashburton treaty, the British government agreed to end the impressment of American sailors. 


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Longley, Robert. "The Webster-Ashburton Treaty of 1842." ThoughtCo, Sep. 26, 2020, Longley, Robert. (2020, September 26). The Webster-Ashburton Treaty of 1842. Retrieved from Longley, Robert. "The Webster-Ashburton Treaty of 1842." ThoughtCo. (accessed June 7, 2023).