Joint maps of the northern boundary of the United States: from the Lake of the Woods to the summit of the Rocky Mountains.

Description

Uncommon 1878 first edition of the Joint Maps of the Northern Boundary of the United States, the landmark U.S.–British atlas that definitively charted the 49th parallel from the Lake of the Woods to the Rocky Mountains.

For a different example at the David Rumsey Map Collection with scans of all the maps, please click here.

This is the first edition of the official atlas produced by the United States Northern Boundary Commission, issued jointly under the direction of Archibald Campbell (U.S. Commissioner) and Donald Roderick Cameron (British Commissioner). It records the monumental field survey that finally established and demarcated the western portion of the U.S.–Canadian boundary, from the Lake of the Woods to the crest of the Rocky Mountains, as defined by the Treaties of 1818 and 1846 between the United States and Great Britain.

The northern boundary had long been a matter of diplomatic and geographic uncertainty. The Treaty of 1818 had fixed the 49th parallel as the line dividing British and American territories from the Lake of the Woods westward to the Rockies, but its precise placement on the ground proved extraordinarily complex. The later Treaty of 1846, which extended the same parallel through the Oregon Country to the Pacific, intensified the need for accurate topographic definition. The work of the Commission was delayed by the San Juan water boundary dispute, the American Civil War, and the construction of the transcontinental railroad, before systematic field operations finally commenced in the 1870s.

Between 1872 and 1876, joint American and British survey parties—each operating under military and engineering officers—conducted painstaking astronomical observations, triangulations, and topographical surveys through some of the most remote and rugged terrain in North America. Their efforts resulted in the construction of stone cairns, iron posts, and earth mounds to mark the 49th parallel, as well as a comprehensive cartographic record. The 25 maps compiled in this atlas combine precision geodesy with detailed naturalistic rendering, showing rivers, lakes, escarpments, and the newly opened trails and settlements along the frontier.

Publication information

The atlas was published in 1878 by the U.S. Government Printing Office, with engraved plates executed under the supervision of the Corps of Engineers. Each map is labeled as a “Joint Map,” emphasizing the bilateral nature of the survey and the cooperative role played by both British and American teams—an early and successful example of international boundary demarcation achieved through scientific collaboration rather than conflict.

Copies of the Joint Maps were distributed only to government departments, foreign offices, and select scientific institutions; they were never offered commercially, accounting for their rarity today. The work stands as a cornerstone of North American boundary cartography, marking the definitive conclusion of nearly a century of territorial negotiation and exploration along the northern frontier.