Defending McClellan: In depth

Not only did Gen. George B. McClellan act quickly when he was delivered a copy of Gen. Robert E. Lee's plans, he also struck a heavier blow against a Confederate army that was larger than previously thought. Related article


  • S.O. 191
  • Rebel casualties
  • Rebel strength

When did McClellan get Lee's plans?

Most histories of the Antietam Campaign assert that McClellan was given Gen. Robert E. Lee's plans in Frederick, Md. at noon, Sept. 13. They then claim he stalled 18 hours before acting on the find. Overlooked evidence contests this claim.


Early in the morning of Sept. 13, most of the Union army was on the move to Frederick, Md. including McClellan, who was relocating his headquarters there from Urbana. At the conclusion of the march, a member of the 27th Indiana Regiment, a unit of the 12th Corps, found a copy of Lee's orders. What time this "Lost Order" was found, and when McClellan received it, has been relatively unchallenged until recently.

What McClellan's detractors argue:

A. McClellan had the Lost Order by noon as is proven by the telegram from him to Lincoln that is dated "12M" for Meridian.

B. McClellan waited 18 hours before moving his troops after finding the Lost Orders



Did McClellan really have the "Lost Order" by noon?

SOURCE: Library of Congress.


1. The original telegram received by War Department is clearly dated "12 Midnight".

2. In the disputed telegraph, McClellan wrote Lincoln, "We have possession of Catoctin [Mountain]," yet the two passes were still held by the Confederates at noon. The Braddock Pass was not gained until 1 p.m. and the Jefferson Pass further south was not taken until near sunset.

3. The Lost Order was not found until after the 12th Corps, of which the 27th Indiana Regiment belonged, ended its morning march. At least five accounts show that the Corps completed its march about noon, which would make it impossible for McClellan to have written and sent a telegraph that contained information about the Lost Order at the same time it was found.

4. The Evening Star newspaper reported that McClellan arrived in Frederick at 11 a.m. and was welcomed by a joyous crowd of more than 5,000 residents. From the reports of his wild reception, it seems unlikely that he would have been able to break away from the crowd and transmit the telegram within the first hour of his arrival.

5. McClellan states in his 11 p.m. telegram to General-in-Chief Henry Halleck that the Lost Order fell into his hands in the "evening", not the morning. It would be highly unusual for McClellan to inform his immediate superior of the find 11 hours after writing to the President.

6. McClellan issued orders at 3 p.m. for his cavalry chief to verify that the Lost Order was not a trick. It seems out of character for someone who is normally considered so cautious to confidently inform Lincoln of the find three hours before he tried to confirm the accuracy of its contents.

7. The Signal Corps reported that "in the evening" it transmitted a message from Lincoln to McClellan, and a return message from McClellan to Lincoln. The report mentions no other transmittal of information between the two men at any other time of the day.


Did McClellan waste time after receiving Lee's plans?

1. The Union cavalry fought the Confederate cavalry to the base of South Mountain until sunset.

2. Burnside's entire 9th Corps of some 13,000 men marched out of Frederick and filled the only road west to Lee's rear guard at Boonesboro from 3:30 p.m. until after 3 a.m. the following morning.

3. A detachment of the 9th Corps in conjunction with cavalry marched from Frederick and took the southern Catoctin pass at Jefferson before sunset.

4. The 6th Corps, about 12,000 men, marched from Buckeystown to the gap in the Catoctin at Jeffersonville, from the evening until at least 10 p.m. A night march beyond that point would have been risky since it was not known precisely where the Confederates were in the valley beyond.

5. The 1st Corps, about 10,000 men, marched to Frederick the evening of Sept. 13. to be ready for an advance on the Confederate rear-guard the following morning.




Sources confirming movement of the 9th Corps on Sept. 13 after the Lost Orders are found.

Note: The 9th Corps was at Frederick, Md., on the morning of Sept. 13.


9th Corps

From the Official Records of the War of the Rebellion

9/13/1862 3:35 p.m. Cox ordered to support Pleasonton at Middletown. Official Records, v.107, p.827

9/13/1862 No time - "Maj. Gen. Reno instructs me to direct you [Wilcox] to put your column in motion for Middletown." O.R., v.107, p.828

9/13/1862, 6:20 p.m. "A division of Burnside's command started several hours ago to support him [Pleasonton] The whole of Burnside's command, including Hooker's corps, march this evening and early tomorrow morning..." O.R., v.27, p.45

9/13/1862, Night-Reno's corps at Middletown-MD except Rodman's division at Frederick-MD, O.R., v.77, p.48

9/13/1862, 11 p.m "Portions of Burnside's and Franklin's Corps moved forward this evening..." in response to S.O. 191, O.R., v.28, p.282


STURGIS'S DIVISION - 9th Corps

6th New Hampshire

Sixth New Hampshire regiment in the War for the Union, Captain Lyman Jackman, c.1891, p.98

9/13-"Came up with enemy at South Mountain."


48th Pennsylvania

The 48th in the War, Oliver Christian Bosbyshell, c. 1895, p.74

9/13 - At stone bridge over Monocacy. "The start on the thirteenth was not made until 3:30 p.m., and the tramp through Frederick was a perfect ovation... Leaving the town by the pike, a march of eight miles brought Middletown in view, when at 9:30 p.m. camp was made." A bright full moon.


21st Massachusetts

Regimental history, pgs. 187-188

"Soon after noon we received marching orders, and passed through the main street of the beautiful old town of Frederick...On our passage through the town, we witnessed General McClellan's enthusiastic reception: as he appeared, the people gave themselves up to the wildest demonstrations of joy; and a dense crowd, mainly composed of women, breaking through all restraint blocked the street around him, laughing and crying in hysterical excitment they tried to get closer and closer to the delivering leader. Our gallant brigadier couldn't let us part without at least a salute in honor of our reception; so the brigade was halted in the street, and the regiments faced to the front; but before arms were presented, General Reno, displeased at the block of the marching column, gave him an emphatic order to right face his men, and attend to business. After a march of about 10 miles we went into bivouac near Middleton, close under the South Mountain range."


35th Massachusetts

Regimental history, p. 25

"By the middle of the afternoon the skirmish in front had abated, and orders came to move forward... At a corner of the streets, General McClellan with his staff reviewed the troops, and cheer after cheer rent the air as the regiments passed... Darkness gathered, but the march was continued. The road was ascending, passing over the Catoctin range of hills, outliers of the Blue Ridge... The waning moon rose and was reaching the zenith, when, late at night, descending the hills we found ourselves int he valley near Middletown."


9th New Hampshire

Regimental history, p. 58-59

"At four o'clock the Ninth showed up in brigade line for the first time... Through the city, beyond the city, along the flinty and dusty pike, the line drags wearily along. The Catoctins grow nearer; the sun sinks behind them; the men clamber up the steep ascent' the moon is high above them, and still they plod along in strange, weird, and ghostly procession.. They pass the summit, and begin the descent. Far as the eye can reach, the spectral line, but dimly described in the distance, stretches away in the valley before them, as before it had lengthened behind... But midnight approaches; the line dissolves; the men stumble into an adjacent field, drop upon the restful ground, and all is forgotten."


WILCOX'S DIVISION - 9th Corps

17th Michigan

A Soldier's Diary, p.10

"Toward evening of the 13th we left Frederick City and marched out on the National Turnpike toward South Mountain and halted for supper and a few hours rest near Middleton. It was nearly midnight. We had made a rapid march of several miles and were tired and hungry as wolves."


100th Pennsylvania

Diary of Infantryman Pettit, p. 23

9/13 "In the evening we took up our march through Frederick toward Middleton a short distance from which we camped."


45th Pennsylvania

Regimental history, pgs. 47-48

"The regiment reached Frederick [actually Middletown] on Saturday evening, Sept. 13th. We were ordered to have everything in readiness to meet the enemy. Next day. while the church bells were ringing and several of the boys had passes to attend divine services, and were brushing up for the occasion, the "fall in" call was sounded, and instead of attending church were ordered into line. After proceeding about five miles we came within range of the artillery fire of the enemy, the shells exploding over us, and grape and canister came hurtling through the trees, in some instances almost destroying them."


79th New York

Regimental history, pgs. 229-230

"We had marched a long distance out of our way in returning from picket duty, and when, at nightfall, we approached Frederick [from the North], the men were tired and hungry... Passing through the city we bivouacked for the night a short distance beyond. At about nine o'clock on the morning of the 14th we overtook the corps and soon reported at brigade headquarters."


RODMAN'S DIVISION - 9th Corps

Connecticut During the Rebellion, p. 261, c.1869

"The 9th Corps under Reno, was still in the advance; and it pressed on, reaching the gap before sundown of the 13th."


4th Rhode Island

Regimental history, p. 140

9/13 "At 9 o'clock the next morning, the line started on again, marching through the city of Frederick, and were received by the inhabitants... Just before reaching Middletown, the rebel rear guard was struck and stoutly resisted our advance, but after a spirited contest, they were force to retire, and the regiment advancing to the town, encamped for the night."


COX'S DIVISION - 9th Corps

Battles and Leaders, p.584

"The other two divisions of our corps crossed the Catoctin in the evening and camped near the western base of the mountain. My own camp was pitched on the western side of the village of Middletown."


11th Ohio

Regimental history, p. 71

"Cox's Division laid in line of battle a mile or two beyond Middletown during the night of the 13th, and early the next morning [Sunday] moved forward."

Confederates suffered greater losses

After the Antietam campaign, Confederates reported 3,966 men either killed or missing. There is no captured column in their reports, which has led historians to assume that prisoners of war were counted among the missing.

Confederate casualty reports total

Note: Casualties above calculated by totaling the following reports from the Official Records of the War of the Rebelllion (O.R.), Vol. 27, pages, 843, 861, 862, 888, 925, 974, 975, 983 and 1026.



McClellan's report after the campaign contrasts sharply with Confederate reports. Although Gen. George B. McClellan could only estimate the number of rebels wounded, his men held the battlefield so his officers could count the number of Confederate dead they buried, the captured Confederate wounded in their hospitals and the captured Confederate prisoners of war added to their prisons.

Confederate casualties as reported by McClellan

Source: O.R., Vol. 27, page 67



Excluding McClellan's wounded estimate, he reported 8,700 killed and captured, some 4,700 more casualties than the Confederates acknowledge. This difference may seem shockingly high, especially because McClellan has a reputation for overestimating enemy forces on the field of battle, but the evidence available strongly supports his report.


Confederates killed

One way to obtain a reasonable estimate of actual Confederate dead can be made by examining the four main cemeteries where these Confederates are now buried.

Confederate burials

All dead listed above are from the Antietam campaign only. Information on the original grave sites of those buried on the battlefield can be found on the Western Maryland Regional Library website. Confederates included from Stonewall Cemetery died between late September 1862 and Nov. 30, 1862.



Most of the rebels killed outright during the campaign were buried near where they fell and years later reinterred at Washington Confederate Cemetery in Hagerstown. Other captured Confederates who perished in Union hospitals in Frederick are buried at Mt. Olivet Cemetery. Mortally wounded Confederates who were unable to travel far were carried to hospitals just across the Potomac River from the battlefield at Shepherdstown. When they died, they were buried at Elmwood Cemetery. Hundreds more wounded made the long journey to hospitals in Winchester, where within two months they succumbed to their injuries. They are buried in the city at Stonewall Cemetery. It is also believed that hundreds of Confederates were never removed from the battlefields and still lie there in unmarked graves.


The number of dead from Antietam at the Washington Confederate cemetery in Hagerstown alone exccedes rebel accounts by almost 1,000.



Confederates captured

The number of rebels McClellan captured can be verified by reviewing the numbers of wounded Confederates in Union hospitals and by examining the flow of prisoners of war from the front to temporary holding facilities, and finally to where they were exchanged.


McClellan's medical director, Jonathan Letterman, reported after the campaign that he had 2,500 wounded Confederates under his care. Undoubtably, some of these men died in Union hospitals and likely account for those buried in Frederick as well as a few of those buried in Hagerstown.


At the same time, unwounded Confederates captured from the campaign were sent to Fort Delaware, near Wilmington, and Fort McHenry in Baltimore. On Sept. 15, General John E. Wool, who commanded forces in Maryland not under McClellan's control, was ordered to send all captured rebels from the pending battles to Fort Delaware. The first wave of prisoners, 1,400 in all, came from the battle of South Mountain. They were sent from Frederick to Baltimore on Sept. 17 as the battle of Antietam raged 20 miles away. More followed after Antietam and the number of Confederate prisoners in Fort Delaware swelled from 60 on Sept. 9, to some 3,000 by Sept. 29.


Both sides were anxious to quickly exchange prisoners and on Oct. 8., 2,274 of the Fort Delaware prisoners were returned to Confederate lines. An additional 224 Confederates from Fort McHenry were exchanged on Oct. 18. It is unclear what became of the remaining 700 prisoners at Fort Delaware. They may have been exchanged at a later date or were perhaps over-counted in the Sept. 29. report. Since documentation on these men at the present time can not be found, they have been excluded from the total captured. Even so, the two types of Confederate prisoners total 5,000 men, more than twice the amount reported by the rebels.



Confederate killed and captured estimate compiled by author


Adding together the rebel dead in the cemeteries, the wounded in the Union hospitals and the captured from the two forts, the total Confederate killed and captured comes to more than 8,268.


This number is not perfect. Certainly many of the dead were initially counted as wounded. But even if the 690 rebels buried by their comrades in Sheperdstown and Winchester are excluded, and an additional 100 are removed from the wounded held by the Federals, the number of casualties still exceeds Confederate reports by 3,500 men. That does not include the rebel bodies never recovered or the additional 700 Confederates reported at Fort Delaware for whom exchange documentation has not been discovered.



Total Confederate casualty estimate compiled by author


Using the Confederates' own number for the wounded and discounting an additional 790 mortally wounded who may have been included in that total, Confederate losses are clearly much higher, thus McClellan did far more damage to Gen. Robert E. Lee's army than previously thought and should get credit for that.

Letterman's report is from the Official Records Vol. 27, p. 111, Captured not wounded from O.R. Vol. 117, pgs. 518, 551, 575, 603, , 589, 603, 607, New York Times Oct. 21, 1862, Washington Evening Star Sept. 9, 1862, 18th Conn. Inf. Regimental, pgs. 32 and 45.



Lee commanded a larger army

On Oct. 10, 1862, three weeks after Antietam, Confederate Gen. Robert E. Lee filed the first full report of the troops under his command. It showed he had 64,273 soldiers present for duty and 76,684 absent, most of the latter being sick and wounded in hospitals stretching from Richmond to Winchester.


Since Antietam, Lee had not been reinforced by a single regiment and what survives of Confederate records strongly implies he had received very few new recruits.


The flow of 18-to-35-year-old conscripts from the draft law had slowed to a trickle since July and the second draft that had been passed by the Confederate Congress two weeks earlier had yet to bring in the thousands of new 36-to-45- year-old conscripts that would swell Lee's ranks again before the December battle of Fredericksburg. Because of these circumstances, we know that the men in Lee's report, in addition to the casualties he received at the engagements of Antietam, South Mountain and Harpers Ferry total up to at least the minimum number of men he would have launched his invasion of Maryland with.


The following chart shows the number of troops in each of Lee's nine divisions, the number of casualties each division lost from Sept. 4 to Sept. 20, and the total men each division must have had at the beginning of the Antietam campaign.


Army of Northern Virginia, Oct. 10, 1862

*Confederate casualties for the Antietam campaign were at least 3,500 higher then shown. It is unclear which divisions suffered these additional casulties. See Confederate casualties for more detail on how these casualties were calculated.


If more than 75,000 men were with Lee during the Antietam campaign, sightings of the different parts of Lee's army should generally match the estimated number of troops from the chart above. In the map below, two-dozen accounts, taken from newspapers, civilians, intelligence reports and the sworn statements of officers, are located on the march routes. The correlation is surprisingly close.


Estimating the size of Lee's Army during the Antietam campaign

When the Confederate army marched, citizens and Union soldiers in their path took note of how many troops passed by.

RESEARCH AND GRAPHICS: Gene Thorp - The Washington Post. Published Sept. 8, 2012.


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