Achieving an effective and clear boundary line between two nations requires patience and hard work over time. Defining this boundary between Canada and the United States started when the Treaty of Paris was signed in 1783 to define the border between British North America and the American states. Over the succeeding years, Canada and the United States appointed a series of temporary Commissions to oversee the boundary surveys, mapping and general maintenance.

In 1794, the Jay Treaty created a Commission to determine the location and source of the St. Croix River. A Commission was mandated in 1858 to survey the border west of the Rocky Mountains and, in 1872 a Commission was set up to survey the border west of Lake of the Woods.

Over the years, 20 agreements, conventions and treaties between four sovereign nations (the United States, Canada, the United Kingdom and Russia) have been negotiated to define the border as people moved westward and then north.

Below is a selection of treaties, conventions, awards and agreements under which the various sections of the international boundary were defined and agreed upon. This is not an exhaustive list - Historians, researchers and history buffs will find in the official reports a wealth of additional information and details about the making of the boundary.

The Definitive Treaty of Peace, 1783

This treaty defined the boundary between the newly established United States of America and the British colonies in North America from the "mouth of the St. Croix River in the Bay of Fundy" to the north-westernmost point of Lake of the Woods, and thence due west to the Mississippi River and down that river.

Jay Treaty of 1794

This treaty provided for two Commissioners to decide which river was the St. Croix, and also provided that if the line west from the north-westernmost point of Lake of the Woods did not intersect the Mississippi River, that the two parties should proceed by amicable negotiations to fix the boundary in that area.

The Treaty of Ghent, 1814

This treaty provided that Commissioners should decide the sovereignty of the several islands in Passamoquoddy Bay, that they should determine the "northwest angle of Nova Scotia" and the northwest head of Connecticut River, and that a map should be made depicting the boundary. "The North Line" section of the boundary, extending from the source of the St. Croix River to the "northwest angle of Nova Scotia" was surveyed and marked under Article V of this treaty. Articles VI and VII provided that the Commissioners should decide the boundary from the 45th parallel to the north-westernmost point of Lake of the Woods. Under this treaty, an agreement was reached upon part of the boundary, but parts of the line through St. Mary's River and at the head of Lake Superior were not agreed upon.

Convention of 1818

Article II of the Convention of 1818 stipulated that the boundary proceed from the north-westernmost point of Lake of the Woods north or south to the 49th parallel and along it to the Stony Mountains (Rockies). The boundary west of that was still undecided.

The Webster-Ashburton Treaty of 1842

Since the Commissioners appointed under the Treaty of Ghent failed to agree on the course of the boundary adjoining the northeastern United States, and since the award of the King of the Netherlands acting under Articles IV, V, of that treaty had been rejected by the United States, it was not until the Webster-Ashburton Treaty of 1842 that an agreement was reached on the boundary from the source of the St. Croix River to the St. Lawrence River. In this treaty, an agreement was also reached on those sections of the boundary through the St. Mary's River to the north-westernmost point of Lake of the Woods, which had not been settled following the Treaty of Ghent.

The Oregon Treaty of 1846

This treaty extended the boundary from the summit of the Rockies westward along the 49th parallel to the Strait of Georgia and south and west through Juan de Fuca Strait to the Pacific. Disagreement as to part of the water boundary through the straits led to arbitration and an award by the Emperor of Germany which was formally accepted in the protocol of 1873.

Convention of 1892

By a convention in 1892 the boundary line was laid down through the islands in Passamoquoddy Bay and a provision was made for a joint survey of the Alaskan boundary from Portland Canal to the 141st meridian.

The Alaska Tribunal Award

With the Klondike gold rush in 1898, the Alaskan boundary question came to the fore. By mutual agreement, in 1899 a provisional boundary was laid down above the head of Lynn Canal and across the Chilkoot and White Passes. In 1903 a convention between the two countries resulted in the creation of the Alaska Boundary Tribunal to resolve the Southeast Alaska boundary question. Following the Award on October 20, 1903, the survey and marking of the boundary was begun by Dr. W. F. King, Dominion Astronomer and Mr. 0. H. Tittman, Superintendent, United States Coast and Geodetic Survey who were appointed as Commissioners under the same convention.

In 1905 a short section of the Southeast Alaska boundary, undefined by the Award, and subsequently agreed upon by the Commissioners, was formally accepted by both countries in an exchange of notes.

In 1906, by a convention, two Commissioners (King and Tittman) were appointed to carry out the survey and marking of the 141st meridian Yukon-Alaska boundary. The field work was finished in 1913.

The Treaty of 1908

In 1908, a treaty was signed which provided for the more complete demarcation of the boundary from the Atlantic to the Pacific and the preparation of accurate modern charts throughout. Although the land sections of the boundary had been marked by monuments, mounds or rock cairns, the water boundary had hitherto been marked on the charts prepared by former Commissioners only as a curved line through the various rivers and lakes on its course, and had not been shown at all on the chart of the St. Croix River. In the treaty of 1908, a provision was made to suitably mark the water boundary by buoys, monuments, and ranges and in such other ways as the Commissioners deemed fitting. The terms of the treaty were to be carried out on each of the various sections of the boundary under the direction of two Commissioners, one to be appointed by each country. For the St. Lawrence River and Great Lakes section, however, the work was undertaken by the International Waterways Commission, (now defunct) which had a membership of three Commissioners from each country.

Treaty of 1910

By a treaty in 1910, the boundary was defined through Passamaquoddy Bay to a point in the middle of Grand Manan Channel.

Treaty of 1925

In 1925, another treaty made minor adjustments to the boundary line at Grand Manan Channel, at the north-westernmost point of Lake of the Woods, and on the 49th parallel, where the boundary was changed from a slightly curved line between monuments to a series of straight lines. In this treaty, a provision was made for the continued maintenance of the international boundary by the Commissioners appointed under the Treaty of 1908, and by their successors.