The NYT, via Flowing Data, brings this map to our attention:
Makes you wonder about all sorts of overlays, doesn’t it?
The NYT describes its provenance:
The 1860 Census was the last time the federal government took a count of the South’s vast slave population. Several months later, the United States Coast Survey—arguably the most important scientific agency in the nation at the time—issued two maps of slavery that drew on the Census data, the first of Virginia and the second of Southern states as a whole.
And, as always, the map tells you about more than geography:
The map reaffirmed the belief of many in the Union that secession was driven not by a notion of “state rights,” but by the defense of a labor system. A table at the lower edge of the map measured each state’s slave population, and contemporaries would have immediately noticed that this corresponded closely to the order of secession. South Carolina, which led the rebellion, was one of two states which enslaved a majority of its population, a fact starkly represented on the map.
Conversely, the map illustrated the degree to which entire regions—like eastern Tennessee and western Virginia—were virtually devoid of slavery, and thus potential sources of resistance to secession.
Much credit to Susan Schulten, the author of the NYT piece. She’s a history professor at the University of Denver and the author of “The Geographical Imagination in America, 1880-1950.”