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NOAA Office of Coast Survey

www.nauticalcharts.noaa.gov/history/CivilWar

Mapping Slavery in the Nineteenth Century

Commercial lithographer Henry S. Graham printed this choropleth map showing the distribution of the 

slave population in September 1861. The map shows in graphic terms the density of the slave population 

in the Southern states, based on figures from the 1860 census. Although the development of this map 

was a collaborative government effort, cartographers working for Edwin Hergesheimer, U.S. Coast 

Survey Drafting Division, created it. 

The development of this map was revolutionary for its time for several reasons. First, it was among the 

first of its kind, initiating a trend of statistical cartography in the United States that allowed the thematic 

mapping of larger social, political, and cultural trends. Second, this map represented an early use of 

statistical information from the census. Third, new techniques in shading developed by Hergesheimer 

were a path-breaking application of these new techniques to human geography. Finally, its makers went 

as far to use “moral statistics” in order to affect political change.

This map was more than a collaborative effort initiated by the federal government; it is a reflection of the 

beliefs of the cartographers and administrators who made it. The United States Coast Survey took the 

statistics from the 8th Census, supervised by Joseph Camp Griffith Kennedy, who was pro-Union and 

created controversy regarding the information to be gathered about slaves. Kennedy wanted to include 
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NOAA Office of Coast Survey

www.nauticalcharts.noaa.gov/history/CivilWar

slaves by name, but Congress refused. Alexander D. Bache, the Coast Survey Superintendent, was also 

pro-Union, and allowed his staff to undertake such a map. Hergesheimer was an immigrant from 

Germany, who left after the failed 1848 liberal revolution in Germany, to lend his expertise to the U.S. 

Coast Survey. Hergesheimer and his German colleagues were largely against slavery and strongly 

supported the Union. 

The map was created to understand the secession crisis, by providing a visual link between secession 

and slavery. The mapmakers consciously limited the map to just the Southern states, including the Border 

States of Maryland, Virginia, and Kentucky, but not the Western slave states of Nebraska, New Mexico, 

and Utah. During and after the war, the map then could be used by the Union to argue that the 

destruction of the Confederacy meant the destruction of slavery. There is a strong message in the banner 

at the top of the map that reads “For the Sick and Wounded Soldiers of the U.S. Army.”

According to artist Francis Bicknell Carpenter, this map was frequently consulted by President Abraham 

Lincoln in considering the relationship between emancipation and military strategy. Carpenter took up 

residence at the White House in February 1864 to paint President Lincoln, after he was inspired by 

Lincoln’s Emancipation Proclamation. Carpenter wrote that Lincoln would look at the map and send his 

armies to free blacks in some of the highest density areas in order to destabilize Southern order.

Carpenter painted the map into symbolic significance in his painting First Reading of the Emancipation

Proclamation of President Lincoln, which is now located in the U.S. Capitol. In this painting, Carpenter 

captures the moment Lincoln announces his decision for emancipation to his cabinet. The slave density 

map is purposely placed in the corner, demonstrating the weight of this proclamation in graphic and 

statistical terms. 

References: 

Francis Bicknell Carpenter (Painter), First Reading of the Emancipation Proclamation of President 

Lincoln. c. 1864. U.S Capitol, Washington, D.C. Accessed 11 Oct 2010.

http://senate.gov/artandhistory/art/artifact/Painting_33_00005.htm.

Harold Holzer, Gabor S. Boritt, and Mark E. Neely, Jr., “Francis Bicknell Carpenter (1830-1900): Painter

of Abraham Lincoln and His Circle,” American Art Journal 16, no. 2 (Spring 1984), 75.

Susan Schulten, “The Cartography of Slavery and the Authority of Statistics,” Civil War History, Volume

56, Number 1, March 2010, 5-32.

Susan Schulten, “Visualizing Slavery,” The New York Times Opinionator, December 9, 2010, 

http://opinionator.blogs.nytimes.com/2010/12/09/visualizing-slavery/