1848 Gilman Map of the United States after the Mexican-American War

A most intriguing 1848 Ephraim Gilman map of the United States issued shortly after the Mexican-American War (1846 - 1848) to advance President James K. Polk's political agenda in his final address to Congress. A remarkable example of carto-advocacy, the map was drawn to address the territorial gains after the war, but is strongly colored by national debates over slavery in the territories.

A Closer Look

The map covers the United States after the Treaty of Guadeloupe-Hidalgo. Gilman divides the country into roughly three major zones, lands east of the Mississippi, lands acquired in the Louisiana Purchase, and lands acquired after the Mexican-American War, including Texas. Statistical tables appear to either side of the map. Color coding identifies various treaty lines keyed to a legend in the upper right.

Carto-Advocacy for Polk's Agenda

The map includes Polk's proposals for Minnesota and Nebraska Territories. It also establishes proposed borders for California, New Mexico, and Texas. Of great interest, Santa Fe is firmly in Texan Territory - reflecting Polk's position on the debate. Another point of great curiosity is the cartographer's failure to recognize the boundaries of Oregon Territory, firmly established by Congress in 1846 - although this act was vigorously disputed by pro-Slavery southern politicians, including Polk himself. On the same note, here the Missouri Compromise line is extended fully to California, reflecting Polk's position that any new states emerging from the new territories be subject to that law. In Polk's home state of Tennessee and neighboring Kentucky, the Cumberland and Tennessee Rivers are erroneously renamed 'Great Kanawha' and 'Big Sandy,' respectively. As pointed out by scholars Mark J. Stegmaier with Richard T. McCulley, this cannot have been an error and may have been a quiet poke at Polk. Otherwise, the map is notable for being rife with spelling and engraving errors, likely the result of being drafted and sent to the engravers on a rushed schedule.

Publication History and Census

This map was drafted in December of 1848 by Ephraim Gilman, Principal Draftsman of the G.L.O., and engraved by P.S. Duval, of Philadelphia. It was prepared for Polk's Message from the President of the United States to the Two Houses of Congress at the Commencement of the Second Session of the Thirtieth Congress, an important document dealing not only with the New Territories, but also addressing the discovery of gold in California. Despite being published in a government document, the separate map is remarkably scarce, both in intuitional collections and on the market - we see just 6 examples in the OCLC, although the full congressional document is somewhat more widely represented.