The Aroostook War was a minor border issue in 1838-1839 between the U.S. and U.K. over the boundary between the colony of New Brunswick and the State of Maine.
This birch back letter carried outside the mail between two Americans on the Northeastern survey expedition above the St. Lawrence River to determine the boundary between U.S. and Canada. The survey party was deployed from Metis River and Lake Metapedia. The letter shows observation points, chronometers, locations and directions. Write-up accompanies, portion of transcript and copy of 27th Congress documents on the survey party which were used on the research etc.