Map of the Canada-US boundary as determined by the 1840s commission
This map was published as part of the official narrative of the British boundary commission. British Commissioner James Estcourt wrote the text in 1847, describing where and how they completed the work. Included in the account are detailed reports of astronomical observations by Major Robinson and Captain Pipon.
<a href="http://static.torontopubliclibrary.ca/da/pdfs/37131055460547d.pdf">North American Boundary. Narrative of the Survey by the British Commission, of the Boundary between the British Possessions in North America and the United States of America, under the Treaty of Washington of 9th August, 1842.</a>