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Field Intelligence in the Shadow of Kennesaw: A Rare Sun Map from Sherman’s Atlanta Campaign

Printed in the field at Big Shanty, Georgia (present-day Kennesaw), on June 10 and 12, 1864, this rare “sun map” of Cobb County was produced by the Topographical Engineers of the Department of the Cumberland at a pivotal moment in General William T. Sherman’s drive toward Atlanta. Created just north of the looming heights of Kennesaw Mountain, the map captures the terrain amid weeks of grueling maneuver warfare, as Union forces sought to outflank Confederate entrenchments west of Marietta. Just over two weeks later, this same landscape would see one of the campaign’s costliest blunders: Sherman’s failed frontal assault on the mountain’s fortified crest. Issued under field conditions and updated in real time, the map exemplifies the Army’s adaptive cartographic response to one of the most challenging operational theaters of the Civil War.

The sheet is a rare surviving example of a Civil War sun map, or photographic contact print, a fragile and ephemeral format used by Union engineers to produce small runs of field maps in campaign settings where full lithographic production was impossible. The map was printed using a salt-print negative process, producing white ink on a light brown ground. This photographic technique, essentially a form of blueprinting in negative, allowed for the rapid duplication of detailed manuscript surveys by exposing sensitized paper directly to sunlight. Although widely used in 1864 and 1865, particularly during the Atlanta, Franklin-Nashville, and Carolinas campaigns, few sun maps survive today due to the instability of the paper and the harsh conditions in which they were used.

This example is further distinguished by the inclusion of an attached update panel at the left margin, titled Additions & Corrections to the Map of Cobb Co. Ga. and printed the same day, June 10. This flap, produced in the same photographic process but strangely two days earlier(?) and mounted to the left of the base sheet, illustrates the evolving intelligence-gathering methods used by engineer officers. Rather than redraw the entire base map, corrections could be issued in modular components and attached in the field. The result is a composite working map that reflects both the scale of the campaign and the immediacy of the decisions being made.

Drawn at a scale of one inch to the mile, the map details the northern half of Cobb County, from Allatoona and (ironically) "unable to locate Lost Mountain" in the west to the Chattahoochee River in the east. Red hand-coloring highlights the major roads radiating from Big Shanty and Marietta. At the same time, a blue wash traces the meandering course of the Chattahoochee River, the final geographic obstacle before Atlanta. Dozens of property owners’ names appear throughout, along with mills, stone quarries, and topographical features rendered in hachure, giving commanders a usable visual index for navigating, quartering troops, and targeting infrastructure. The rugged, high ground near Kennesaw Mountain is depicted in dense relief, underscoring the challenges Sherman faced in trying to flank General Joseph E. Johnston’s entrenched forces.

This map belongs to the final generation of operational cartography produced before Sherman abandoned conventional supply lines and marched to the sea. It is part of a group of campaign-era maps cataloged in Stephenson, Civil War Maps (2nd ed., 1989), no. S60, which includes the “Additions & Corrections” flap. The version without the flap appears as Stephenson S59.