Webster-Ashburton Treaty Is Signed

The Webster-Ashburton Treaty, signed August 9, 1842, was a treaty resolving several border issues between the United States and the British North American colonies, particularly a dispute over the location of the Maine-New Brunswick border.

It also established the details of the border between Lake Superior and the Lake of the Woods, originally defined in the Treaty of Paris (1783); reaffirmed the location of the border (at the 49th parallel) in the westward frontier up to the Rocky Mountains, originally defined in the Treaty of 1818; called for a final end to the slave trade on the high seas, to be enforced by both signatories; and agreed on terms for shared use of the Great Lakes.

The treaty was signed by United States Secretary of State Daniel Webster and United Kingdom Privy Counsellor Alexander Baring, 1st Baron Ashburton. A plaque commemorating the treaty was placed at the site of the old State Department building in Washington, D.C. where the signing occurred.