Mapping the United States-Mexico Boundary: Cooperation and Controversy

Abstract

With two sets of maps, the United States-Mexico boundary was brought into being. Across a wilderness of deserts and mountains, rivers and canyons, the boundary commissions of Mexico and the United States surveyed a line, and from the results of their surveys, each commission produced a set of authoritative maps in which the boundary was defined. From 1849 to 1857, the two commissions carried out the first systematic exploration and mapping of the region that is now the U.S.-Mexico Borderlands. The survey maps, in addition to being the earliest detailed and reliable maps of the region they depicted, became important later in debates over the nature of the boundary. This paper will focus on the U.S.-Mexico boundary survey as a mapping mission, and present some of the maps produced by the two commissions. The maps will be examined and compared, with reference to the records and reports of the two commissions, in order to determine the effects of the interactions between the U.S. and Mexican Boundary Commissions upon some of the maps that resulted from the survey. The cartography of the present-day U.S.-Mexico Borderlands had its beginnings in the sixteenth century, based upon travelers' reports from early Spanish expeditions to the New World. Spanish engineers and missionaries continued to expand geographical knowledge over the succeeding centuries, drawing maps from local observations. Nevertheless, the region was still relatively unknown in the middle of the nineteenth century, when U.S. victory in a war with Mexico led to the present boundary between Mexico and the United States. 1 On February 2, 1848, the Treaty of Guadalupe Hidalg02 brought an end to the Mexican-American War. As a result of the war, Mexico ceded to the United States the Mexi-