How the Hergesheimer Map Influenced Emancipation
In 1861 Edwin Hergesheimer drafted two maps for the United States Coast Survey that implemented shading with patterns to show quantitative data derived from the 1860 census. The information was extracted from the 1860 slave schedules that were collected as part of the United States 1860 census. The two maps are the earliest examples of statistical mapping in the United States. Map of Virginia Showing the distribution of its Slave Population from the Census of 1860 depicts the percentage of slaves in each county with the color gray to highlight those counties with the highest percentages of enslaved peoples. Hergesheimer successfully employed the same techniques in Map Showing the Distribution of the Slave Populations of the Southern States of the United States Compiled from the Census of 1860. Copies of both maps were distributed to military leaders as well as to President Abraham Lincoln and his staff. Lincoln and Sherman were struck by how much strategic information these maps conveyed. Lincoln understood that the lighter defined areas may be the strategically weakest areas because slaves were "statistically non-existent." According to contemporary sources, the map was frequently consulted by President Lincoln and its influence is conveyed by its inclusion in Francis Bicknell Carpenter's painting, First Reading of the Emancipation Proclamation of President Lincoln.
In 1864 General Sherman became the commanding general of the Military Division of the Mississippi and he was under orders from General Ulysses S. Grant to penetrate the Southern interior and inflict as much damage as possible, especially upon valuable war resources. He did just that before the war ended in 1865. In order to wage this total war Sherman needed maps and data. Union topographical engineers mapped the terrain while Sherman studied the 1860 census. The superintendent of the census, Joseph Kennedy, oversaw the creation of maps that reflected census data; they showed not only the distribution of the population but of crops and livestock, courtesy the 1860 agricultural census. This information was crucial to Sherman as he led the army in decimating the Confederacy; they knew exactly where to look for supplies.
By using historical maps produced during the Civil War Sherman strategically targeted large density enslaved populations during his 1864 and 1865 campaigns through Georgia and the Carolinas. By serving as both an emancipating and destructive force, Sherman's strategic targeting of large plantation spaces contributed to the demise of the Confederate economy and way of life by late-April 1865.
The information provided in this description is based upon the work of Susan Schulten as published in the New York Times blog series, Disunion and A History of America in 100 Maps (2018), The Mapping of America (1980) by Seymour Schwartz and Ralph Ehrenberg and Richard Stephenson's and Marianne McKee's Virginia in Maps: Four Centuries of Settlement, Growth, and Development (1999).
Much has been written about Sherman’s march to the sea and through the Carolinas. Recently, Susan Schulten, professor of history at the University of Denver has blogged about Sherman’s march and use of maps in Disunion, a blog published by the New York Times. Anne Sarah Rubin reveals the stories and myths about Sherman’s march in Through the Heart of Dixie: Sherman’s March and American Memory (2014). In 2006 Jaqueline Glass Campbell analyzed the cultural complexities as Sherman marched through the American Southeast in When Sherman Marched North from the Sea: Resistance on the Confederate Home Front.