Cedar Mountain to Antietam

A Civil War Campaign History of the Union XII Corps, July – September 1862

M. Chris Bryan

A hybrid unit history and leadership and character assessment, putting the XII Corps' actions during the battles of Cedar Mountain and Antietam in proper context by providing significant and substantive treatment to its Confederate opponents. The story of a little-studied yet consequential corps which fills a longstanding historiographical gap.
Date Published :
February 2022
Publisher :
Savas Beatie
Illustration :
28 maps, 53 images
Format Available    QuantityPrice
Binding. : Hardback
ISBN : 9781611215779
Pages : 408
Dimensions : 9 X 6 inches
Stock Status : In stock
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The diminutive union XII corps found significant success on the field at Antietam. Its soldiers swept through the East Woods and the Miller Cornfield—permanently clearing both of Confederates—repelled multiple Southern assaults against the Dunker Church plateau, and eventually secured a foothold in the West Woods. This important piece of high ground had been the Union objective all morning, and its occupation threatened the center and rear of Gen. Robert E. Lee’s embattled Army of Northern Virginia. Federal leadership largely ignored this signal achievement and the opportunity it presented. The achievement of the XII Corps is especially notable given its string of disappointments and hardships in the months leading up to Antietam.

M. Chris Bryan’s Cedar Mountain to Antietam: A Civil War Campaign History of the Union XII Corps, July –September 1862 begins with the formation of this often-luckless command as the II Corps in Maj. Gen. John Pope’s Army of Virginia on June 26, 1862. Bryan explains in meticulous detail how the corps endured a bloody and demoralizing loss after coming within a whisker of defeating Maj. Gen. “Stonewall” Jackson at Cedar Mountain on August 9; suffered through the hardships of Pope’s campaign before and after the Battle of Second Manassas; and triumphed after entering Maryland and joining the reorganized Army of the Potomac. The men of this small corps earned a solid reputation in the Army of the Potomac at Antietam that would only grow during the battles of 1863.

This unique study, which blends unit history with sound leadership and character assessments, puts the XII Corps’ actions in proper context by providing significant and substantive treatment to its Confederate opponents. Bryan’s extensive archival research, newspapers, and other important resources, together with detailed maps and images, offers a compelling story of a little-studied yet consequential command that fills a longstanding historiographical gap.

About The Author

Chris Bryan earned a B.S. in History from the United States Naval Academy, an M.A. in Liberal Arts from St. John’s College, Annapolis, and a Masters in Historic Preservation from the University of Maryland, College Park. The former Naval Aviator works as a project manager and lives in southern Maryland with his wife and two children. This is his first book.


“I thoroughly enjoyed this new study on the early days of the XII Corps. Bryan skillfully weaves firsthand accounts into a compelling story about the triumphs and defeats of this venerable unit. Unlike so many other unit histories, he provides context by explaining the Confederate side of the equation and goes one step further by devoting space to the topography of the battlefields. These approaches help the reader gain a much better grasp of the issues and challenges the XII Corps faced. Hal Jespersen’s outstanding maps are abundant and effectively complement the text. This study thrusts armchair readers into the ranks of the XII Corps, where they can almost see, smell, and hear the sounds of camp, the march, and the battles. I wish all unit history books were this good.”

- Bradley M. Gottfried, author of "The Maps of Antietam"

“This is a terrific book! Chris Bryan’s deep research and concise prose shines new light on the often-overlooked travails and valor of ‘Banks’ Weary Boys’ as they became the XII Corps, Army of the Potomac at Antietam. I highly recommend it.”

- Thomas G. Clemens, editor of "The Maryland Campaign of September 1862" trilogy

“Deeply researched and accompanied by splendid battle maps, Chris Bryan’s book is an engaging microhistory of the Union Army’s XII Corps during the crucial summer and fall of 1862. In addition to providing a clear and comprehensive narrative, Bryan has marshaled a myriad of soldier’s voices to create a vivid portrait of life in the Union Army during its most trying period.”

- Craig L. Symonds, Professor Emeritus, United States Naval Academy

“The XII Corps was something of an ugly stepchild in the Union Army and did not often get full credit for its battlefield performance. Chris Bryan’s richly sourced narrative helps bring the XII Corps and its remarkable story from Cedar Mountain to Antietam out of the shadows.”

- D. Scott Hartwig, author of "To Antietam Creek: The Maryland Campaign of September 1862"

Cedar Mountain to Antietam brings relief to the deeds of an organization and men history has left behind. Chris Bryan tells the story of the XII Corps as its soldiers would have wanted it done: with good writing, excellent storytelling, deep research, and a close focus on their successes, struggles, and sacrifices. This book will be an essential source for those interested in the Army of the Potomac or the campaigns of Cedar Mountain, Antietam, or Second Manassas.”

- John Hennessy, author of Return to "Bull Run: The Campaign and Battle of Second Manassas"

“The study is a deep dive into the very fabric of this corps, the depth of research Bryan brings to the forefront is truly worthy to note. This is a micro-tactical study in the fullest sense of that phrase.”

- Emerging Civil War Book Review

“Where this book shines is the attention Bryan pays to individual accounts - humanizing the campaign in ways that reveal the experiences of combat, a tough nut to crack. Bryan’s use of private correspondence and the OR among a zillion other sources is exceptional.”

- Keith Harris, Keith Harris History

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