EXPANSION, FRAGMENTATION, AND REUNIFICATION 147In early 1864, Union Commander Ulysses S. Grant
instructed General William Tecumseh Sherman and
his army to strike at the heart of the Confederacy.
Sherman and his men were to pursue General Joseph
Johnston’s army into Georgia in order to destroy
the enemy and its resources. Grant’s directive
became the basis for the Atlanta Campaign, in which
Sherman’s armies marched from northwest Georgia
to Atlanta from May to September. Sherman then
spread his men up to sixty miles wide on a march
toward Savannah before heading north through the
Carolinas. The timing of the campaign was crucial:
it brought Georgia to its knees and gave the Union
a crucial military victory. This in turn contributed to
the re-election of President Lincoln in November.
Sherman’s march has been judged brilliant and
brutal, necessary and vindictive. Either way, it was the
most ambitious campaign of the war, for it required
him to take his armies far beyond the reach of Union
lines. To execute the mission, Sherman relied on a
crack team of mapmakers in the field who delivered
detailed profiles of the terrain that were far superior
to those of the enemy. But before Sherman even
arrived in Georgia he immersed himself in census
data to learn how and where his men could survive
off the land after they were cut loose from their
GENERAL SHERMAN AND THE LOGIC OF DESTRUCTION
Map of Georgia (1839), annotated
for military use, circa 1864
chain of supply. Early in the war he even asked the
superintendent of the Census for strategic maps of
Southern resources, seeking to harness this data for
military purposes.
The Census Office had been experimenting
with data maps since the beginning of the war in
the hopes of aiding Union forces. Among the most
relevant of these efforts for Sherman was this large
1839 postal map of Georgia, which marked roads
and rivers. This limited information was ideal, for it
enabled clerks to add new counties, then to annotate
each with data from the most recent census. As
shown in the updated legend, each county listed the
population of whites, “free coloreds,” slaves, and
men of military age. That final figure enabled the
army to calculate roughly how many men would be
serving in the Confederate forces, and likely absent
from the region.
The information on resources and livestock was
just as valuable, for the war had turned routine
census data into military intelligence. Corn and
hogs could be eaten, while sugar and cotton could
be burned. The information on slavery was no less
useful. Sherman’s army encountered approximately
90,000 slaves in the Georgia campaign: they
constituted more than half of the population
then present in those counties. A total of 14,000
emancipated men, women, and children attached
themselves to his army. Those left behind struggled
to survive, for Sherman attacked not just the
Confederacy but also its food. By destroying corn
as well as cotton, he subjected the weakest members
of society to the greatest deprivation.
Sherman’s actual march through Georgia was
no doubt guided more by the sophisticated maps
produced by his team of mapmakers and surveyors,
as well as the terrain itself. But his quest to harvest
this census information did prompt some of the
nation’s early data maps. These hastily compiled
documents, in turn, helped Sherman to conceive
and to undertake the operation in the first place.
The general admitted as much at the end of the war,
writing that the information supplied by the Census
Office helped his armies to identify supply routes
“which otherwise would have been subjected to blind
chance, and it may be to utter failure.” Armed with
this information, he wrote, “I knew exactly where
to look for food.” Without it, “I would not have
undertaken what was done and what seemed a puzzle
to the wisest and most experienced soldiers of the
world.” In other words, it was the data that enabled
Sherman to see what was possible as he prepared a
march that shattered Confederate resolve.