Reconnaissance Maps (Six Sheets and Profile) Showing the general features of the topography adjacent to the 49th parallel from the Lake of the Woods to the Rocky Mountains.

A group of 7 maps that helped finalized the water boundary between the United States and British Canada.

Although the official conditions defining the boundary between the majority of the United States and Canada (with the notable exception of the Oregon Territory) were set by the Treaty of 1818, a number of unknowns remained. Several references were made to watersheds or river drainages, although their precise location hadn’t yet been determined. In 1872, over five decades later, The International Boundary Survey was established to definitively determine the border between the Lake of the Woods and the Rocky Mountains.

The American team was led by Archibald Campbell and their results were published in Washington by the Government Printing Office in 1878. The report included the seven folding sheets seen here – six maps detailing the results of the survey commission, plus a seventh that shows the elevation profile of the route. Apart from geographic information, the maps contain a wealth of contemporary details regarding local Native American tribes, transportation routes, and various western landmarks.