How Many Men Where In The Sunken Road?

The area between the Piper Farm and the Sunken Road was a killing ground. Soldiers moving through there were highly exposed. In that sense the Sunken Road was a trap in addition to being a breastwork, as it was difficult if not impossible for any troops to move forward toward the road or retreat from it once there without sustaining heavy losses.
Much the same is true of most defensive works though, at least the point about retreating. It's a fairly consistent rule that if an attack stalls out before reaching the defences, it's lopsided; if it penetrates into the defences and forces a retreat, the casualties suffered by the defenders during their retreat sort of "even out" a lot of the casualties the attackers suffered.
 
The area between the Piper Farm and the Sunken Road was a killing ground.
What Federal batteries were firing onto the Piper Farm and from where?
Batteries supporting the Federal advance on the Sunken Road were:
1. Tompkins' Battery (1st Rhode Island Light, Battery A,6 x 10pdr Parrotts) appeared at 9.30am II Corps, 2nd Division on high ground opposite Dunker Church. Its involvement can be judged by the fact that it suffered 19 casualties.
2. Owen’s battery (1st Rhode Island Light, Battery G, 6 x 3” Rodman Rifles) replaced Tompkin’s battery at about 11.00-11.30am as Tompkin’s battery had to withdraw as ammunition was low. It suffered 5 casualties.
3. Graham’s battery (1st United States Artillery, Battery K, 6 x 12pdr Napoleons) was part of the Artillery Reserve and was brought across Antietam Creek to support the Union centre. Graham’s battery arrived on the Roulette Farm at about 10.30-11.00am and proceeded toward the battle raging around the Sunken Road. Maj. Gen. Israel Richardson was on foot and placed this battery personally near the eastern corner of Bloody Lane. The battery suffered a total of 9 killed and wounded. It was later on in the day as Richardson was organising a safer spot for this battery to withdraw to, that he was mortally wounded.
4.1st Rhode Island Light, Battery B (Hazard's Battery) and 1st New York, Battery G (Frank's Battery) were part of the divisional artillery with II Corps but neither were in a position to support the attack on the Sunken Road.
This basically leaves batteries from the Union Artillery Reserve posted on the far side of Antietam Creek. I presume these would be Von Kleiser’s Battery 1st New York Light Artillery, Battery B and Langner’s Battery, 1st New York Light Artillery, Battery C both armed with 4 x 20pdr Parrotts which would be firing at long range. How these batteries directed their fire I am unsure. Was it possible to see across the Piper Farm from where these batteries were positioned to direct the fall of shot?
 
What Federal batteries were firing onto the Piper Farm and from where?
Batteries supporting the Federal advance on the Sunken Road were:
1. Tompkins' Battery (1st Rhode Island Light, Battery A,6 x 10pdr Parrotts) appeared at 9.30am II Corps, 2nd Division on high ground opposite Dunker Church. Its involvement can be judged by the fact that it suffered 19 casualties.
2. Owen’s battery (1st Rhode Island Light, Battery G, 6 x 3” Rodman Rifles) replaced Tompkin’s battery at about 11.00-11.30am as Tompkin’s battery had to withdraw as ammunition was low. It suffered 5 casualties.
3. Graham’s battery (1st United States Artillery, Battery K, 6 x 12pdr Napoleons) was part of the Artillery Reserve and was brought across Antietam Creek to support the Union centre. Graham’s battery arrived on the Roulette Farm at about 10.30-11.00am and proceeded toward the battle raging around the Sunken Road. Maj. Gen. Israel Richardson was on foot and placed this battery personally near the eastern corner of Bloody Lane. The battery suffered a total of 9 killed and wounded. It was later on in the day as Richardson was organising a safer spot for this battery to withdraw to, that he was mortally wounded.
4.1st Rhode Island Light, Battery B (Hazard's Battery) and 1st New York, Battery G (Frank's Battery) were part of the divisional artillery with II Corps but neither were in a position to support the attack on the Sunken Road.
This basically leaves batteries from the Union Artillery Reserve posted on the far side of Antietam Creek. I presume these would be Von Kleiser’s Battery 1st New York Light Artillery, Battery B and Langner’s Battery, 1st New York Light Artillery, Battery C both armed with 4 x 20pdr Parrotts which would be firing at long range. How these batteries directed their fire I am unsure. Was it possible to see across the Piper Farm from where these batteries were positioned to direct the fall of shot?
There was ling range artillery from the other side of Antietam Creek. But in addition to artillery, any infantry fire that overshot the Sunken Road would have impacted this area.
 
View attachment 391130
*photo by @kholland
thread: https://civilwartalk.com/threads/the-irish-brigade-attacks-the-sunken-road.119355/#post-1230043


First you would think a description of the Sunken Road would be fairly straight forward, Pierro editing Carmen on page 282 describes it as;

From the Hagerstown Road the sunken road runs easterly for 550 yards, then turns nearly southeast 450 yards to where it makes an angle and runs nearly south. For the first 100 yards the road is level, then rises to pass over a rock ledge, descends but little and again rises to another rock ledge where it turns southeast. From this last rock ledge (the angle in the road) it descends 80 yards to the mouth of the Roulette lane, the descent in the eighty yards being twenty feet. From the mouth of the lane the road begins to ascend, and at 150 yards reaches the plateau upon which it runs to its southerly course.

I believe this is a printing error as the distance from the Hagerstown Pike to the angle is more like 450 yards, just look on any map and the distance from the Pike to the angle and from the angle to where the road turns southwards are similar distances – 450 yards. This gives a total length of 900 yards.

The road was filled with the following troops from left to right:

1. Remnants of Cobb’s and Colquitt’s brigade plus some men from 23rd North Carolina and 13th North Carolina (from Garland’s brigade)

2. Five regiments of Rodes’ brigade consisting of 26th Alabama, 12th Alabama, 3rd Alabama, 5th Alabama and 6th Alabama.

3. Four regiments of G.B. Anderson’s brigade with 2nd North Carolina, 14th North Carolina, 4th North Carolina and 30th North Carolina.

The numbers for G.B. Anderson’s brigade reported by Carmen are thought to be realistic at 1,174 men. We know that the right flank finished short of the turn southwards as Wright’s brigade was able to join the end of the line later on, therefore G.B. Anderson’s brigade held a frontage of about 325 yards. This gives a density of about 3.6 men per yard – in line with our estimate of between 3 to 4 men per yard as given in the training manuals.

Rodes described his position with the right flank being 80 yards west of the Roulette Lane (this is the point where the road turns southeast) and his left flank was 150 yards from the Hagerstown Pike. This gap was the space where Colquitt’s brigade was stationed. This is a distance of 300 to 325 yards, yet Carmen gives the strength as 850 (as reported by Rodes?). If this were the case it would only give a density of 2.6 men per yard, a density equivalent to that of a single line! Alternatively, if G.B. Anderson’s brigade had a similar density to this it would occupy a frontage of 450 yards, over 100 yards more and would reach the point where the lane turns south thereby leaving no gap for Wright’s brigade. This suggests that Rodes must have had more than 850 men. If we assume a similar density as G.B. Anderson’s brigade, Rodes’ brigade would number at least 1,200 men. With only 800 men, there would be a gap of close to 100 yards which would be visible from the Union side, which was not commented upon.

Is this reasonable from what we know was reported at the time? Carmen states that the conformation of the ground in the Sunken Lane determined the position of the troops. The gap between the two brigades therefore coincided with the turn in the road as the ground falls away at that point. With perhaps only a small gap between the brigades, with a density of about 3.5 men per yard means the lane is capable of holding far more troops than what is reported and is once again suggestive that Rodes’ brigade especially contained more men than the 850 reported. This contrasts with G.B. Anderson’s brigade that contained the number reported.

The lane had to be full of men as any gap between regiments or brigades of the sizes we have suggested with Rodes’ brigade, would be noticed by the attacking Union forces as these would be seen as vulnerable parts in the line to assault.

Now let us now consider Wright’s brigade from R.H. Anderson’s division. The disintegration of R.H. Anderson’s division can be seen by the simple fact that there are no official reports from any of its brigades. So, in the O.R. there is no divisional report, none of six brigade reports and only a single regimental report (16th Mississippi) from the 26 regiments present! Therefore, a lot of what happened to these brigades is open to conjecture (1 document present in the O.R. from a possible 33!!).

Wright’s brigade tore down the strong oak picket fence that was on the lane side of Piper’s apple orchard. At this time the brigade suffered from artillery fire from Tompkins’ battery and from batteries on the other side of Antietam creek. Whilst travelling through the orchard, Wright’s iron-grey horse was torn to pieces by a shell, Wright himself being thrown to the ground. He then led his brigade on foot. Wright was further injured probably passing through the cornfield and it is said only about 250 men reached the Sunken Lane. Control of the brigade went to Col Robert H. Jones of 22nd Georgia. On reaching the lane the brigade had the following order from left to right: 22nd Ga. 44th Al. 48th Ga. 3rd Ga. We also know the brigade went prone on reaching the lane.

It was this section of the Sunken Lane that whilst not under fire from Tompkins’ battery, it was however enfiladed by batteries on the other side of Antietam creek.

The first question to consider is the 250 men reaching the lane a reasonable assumption? The brigade of 4 regiments had a reported strength of 521. The total reported losses were 203; 16 KIA, 187 WIA, 34 MIA. Let us assume 520 men set foot onto Piper’s farm. If only 250 men reach the lane that means 270 men are lost on the Piper farm i.e., greater than the total reported loss for the battle. Not only that, but there must be no losses when the brigade is in the lane – an impossible scenario.

We know some men might be left behind when crossing the Piper farm, but the figures just do not add up. So, what might be a more probable outcome? The first assumption is that it is more than probable that more casualties would have occurred in the vicinity of the sunken lane. If not in the lane itself, as it was enfiladed by union batteries on the far side of Antietam Creek, then either side of the lane; the cornfield they moved through obviously would have been under fire and the brigade would eventually advance out of the sunken lane to attack Union forces on the far side of the lane.

What might be the alternatives? First let us assume that 1/3 of the casualties occur crossing the Piper farm. This equates to 68 men, leaving about 450 men reaching the lane. Alternatively, if 2/3 of the losses occur crossing the farm, this still leaves 385 men reaching the lane. Either way this means about 400 men reach the lane to fit into a gap of 100-120 yards giving a density of between 3.3 and 4 men per yard. If only 250 men reached the lane at a density of 3.3 men per yard would only occupy a frontage of 75 yards, thereby leaving a noticeable gap in the line.

In the meantime, Col. Robert H. Jones who leads the brigade into the lane becomes a casualty (interestingly so unpopular in his own regiment that some say he was shot by one of his own men!) and leadership of the brigade passes to Col. William Gibson of 48th Georgia, who after the battle is reported by D.H. Hill as being totally unsuited for brigade command. It was Col. Gibson who apparently decided to attack out of the Sunken Road although Wright (who had been carried to the Sunken Road on a litter) may have prompted the attack.

We now have the gap from the Mumma Lane junction to the Hagerstown Pike, a distance of 150 yards. If our estimate of 3.6-3.7 men per yard is reasonable, how many men could fit into this space? This gives values of 540 to 560 men. The remnants of Colquitt’s and McRae’s brigade are believed to be in the region of 200 men and at the junction with the Turnpike was Cobb’s brigade thought to be about 350 men. This means that the total number of 550 men is a reasonable estimate and would fit into the gap at a density similar to elsewhere in the Sunken Road.

The assumptions used in this method of considering regimental and brigade frontages seems to be a reasonable one. A density of around 3.5 to 4.0 men per yard seems to be consistent with a regiment formed as a double line, and as both sides utilised the same or similar training manuals this value can be applied to both sides in the conflict. However, this method again signifies that in some specific cases outlined above, the reporting of the number of some of the Confederates brigades at Antietam is questionable.

Finally, what would be the likely number of men that defended the Sunken Road? If we assume a density of 3.6 men per yard for 900 yards gives a total of 3,240 along its entire length. If we subtract the number from Wright’s brigade that arrived later and assume this to be about 440, then the figure falls to 2,800 men. What units make up this number? The remnants of various brigades stretching from the Hagerstown Pike to the Mumma farm lane at 550 men, G.B. Anderson’s brigade of about 1,200 men thereby giving a value of about 1,050 men for Rodes’ brigade. These numbers give a similar troop density right across the sunken road which is not an unreasonable assumption. Even if we allow gaps between each individual regiment and slightly larger gaps between brigades we would attain very similar numbers.
Hey, thanks for the subject matter and I really appreciate the effort you guys have gone through to figure these things out. A little more involved than I normally get but I do appreciate the information and the tone of the discussion.
I focus on uniforms, equipment, and weapons mostly. I like to present accurate Living History when I can and these type of discussions are great to read along with and soak up information that I normally wouldn't pursue.
Cheers!
 
View attachment 391130
*photo by @kholland
thread: https://civilwartalk.com/threads/the-irish-brigade-attacks-the-sunken-road.119355/#post-1230043


First you would think a description of the Sunken Road would be fairly straight forward, Pierro editing Carmen on page 282 describes it as;

From the Hagerstown Road the sunken road runs easterly for 550 yards, then turns nearly southeast 450 yards to where it makes an angle and runs nearly south. For the first 100 yards the road is level, then rises to pass over a rock ledge, descends but little and again rises to another rock ledge where it turns southeast. From this last rock ledge (the angle in the road) it descends 80 yards to the mouth of the Roulette lane, the descent in the eighty yards being twenty feet. From the mouth of the lane the road begins to ascend, and at 150 yards reaches the plateau upon which it runs to its southerly course.

I believe this is a printing error as the distance from the Hagerstown Pike to the angle is more like 450 yards, just look on any map and the distance from the Pike to the angle and from the angle to where the road turns southwards are similar distances – 450 yards. This gives a total length of 900 yards.

The road was filled with the following troops from left to right:

1. Remnants of Cobb’s and Colquitt’s brigade plus some men from 23rd North Carolina and 13th North Carolina (from Garland’s brigade)

2. Five regiments of Rodes’ brigade consisting of 26th Alabama, 12th Alabama, 3rd Alabama, 5th Alabama and 6th Alabama.

3. Four regiments of G.B. Anderson’s brigade with 2nd North Carolina, 14th North Carolina, 4th North Carolina and 30th North Carolina.

The numbers for G.B. Anderson’s brigade reported by Carmen are thought to be realistic at 1,174 men. We know that the right flank finished short of the turn southwards as Wright’s brigade was able to join the end of the line later on, therefore G.B. Anderson’s brigade held a frontage of about 325 yards. This gives a density of about 3.6 men per yard – in line with our estimate of between 3 to 4 men per yard as given in the training manuals.

Rodes described his position with the right flank being 80 yards west of the Roulette Lane (this is the point where the road turns southeast) and his left flank was 150 yards from the Hagerstown Pike. This gap was the space where Colquitt’s brigade was stationed. This is a distance of 300 to 325 yards, yet Carmen gives the strength as 850 (as reported by Rodes?). If this were the case it would only give a density of 2.6 men per yard, a density equivalent to that of a single line! Alternatively, if G.B. Anderson’s brigade had a similar density to this it would occupy a frontage of 450 yards, over 100 yards more and would reach the point where the lane turns south thereby leaving no gap for Wright’s brigade. This suggests that Rodes must have had more than 850 men. If we assume a similar density as G.B. Anderson’s brigade, Rodes’ brigade would number at least 1,200 men. With only 800 men, there would be a gap of close to 100 yards which would be visible from the Union side, which was not commented upon.

Is this reasonable from what we know was reported at the time? Carmen states that the conformation of the ground in the Sunken Lane determined the position of the troops. The gap between the two brigades therefore coincided with the turn in the road as the ground falls away at that point. With perhaps only a small gap between the brigades, with a density of about 3.5 men per yard means the lane is capable of holding far more troops than what is reported and is once again suggestive that Rodes’ brigade especially contained more men than the 850 reported. This contrasts with G.B. Anderson’s brigade that contained the number reported.

The lane had to be full of men as any gap between regiments or brigades of the sizes we have suggested with Rodes’ brigade, would be noticed by the attacking Union forces as these would be seen as vulnerable parts in the line to assault.

Now let us now consider Wright’s brigade from R.H. Anderson’s division. The disintegration of R.H. Anderson’s division can be seen by the simple fact that there are no official reports from any of its brigades. So, in the O.R. there is no divisional report, none of six brigade reports and only a single regimental report (16th Mississippi) from the 26 regiments present! Therefore, a lot of what happened to these brigades is open to conjecture (1 document present in the O.R. from a possible 33!!).

Wright’s brigade tore down the strong oak picket fence that was on the lane side of Piper’s apple orchard. At this time the brigade suffered from artillery fire from Tompkins’ battery and from batteries on the other side of Antietam creek. Whilst travelling through the orchard, Wright’s iron-grey horse was torn to pieces by a shell, Wright himself being thrown to the ground. He then led his brigade on foot. Wright was further injured probably passing through the cornfield and it is said only about 250 men reached the Sunken Lane. Control of the brigade went to Col Robert H. Jones of 22nd Georgia. On reaching the lane the brigade had the following order from left to right: 22nd Ga. 44th Al. 48th Ga. 3rd Ga. We also know the brigade went prone on reaching the lane.

It was this section of the Sunken Lane that whilst not under fire from Tompkins’ battery, it was however enfiladed by batteries on the other side of Antietam creek.

The first question to consider is the 250 men reaching the lane a reasonable assumption? The brigade of 4 regiments had a reported strength of 521. The total reported losses were 203; 16 KIA, 187 WIA, 34 MIA. Let us assume 520 men set foot onto Piper’s farm. If only 250 men reach the lane that means 270 men are lost on the Piper farm i.e., greater than the total reported loss for the battle. Not only that, but there must be no losses when the brigade is in the lane – an impossible scenario.

We know some men might be left behind when crossing the Piper farm, but the figures just do not add up. So, what might be a more probable outcome? The first assumption is that it is more than probable that more casualties would have occurred in the vicinity of the sunken lane. If not in the lane itself, as it was enfiladed by union batteries on the far side of Antietam Creek, then either side of the lane; the cornfield they moved through obviously would have been under fire and the brigade would eventually advance out of the sunken lane to attack Union forces on the far side of the lane.

What might be the alternatives? First let us assume that 1/3 of the casualties occur crossing the Piper farm. This equates to 68 men, leaving about 450 men reaching the lane. Alternatively, if 2/3 of the losses occur crossing the farm, this still leaves 385 men reaching the lane. Either way this means about 400 men reach the lane to fit into a gap of 100-120 yards giving a density of between 3.3 and 4 men per yard. If only 250 men reached the lane at a density of 3.3 men per yard would only occupy a frontage of 75 yards, thereby leaving a noticeable gap in the line.

In the meantime, Col. Robert H. Jones who leads the brigade into the lane becomes a casualty (interestingly so unpopular in his own regiment that some say he was shot by one of his own men!) and leadership of the brigade passes to Col. William Gibson of 48th Georgia, who after the battle is reported by D.H. Hill as being totally unsuited for brigade command. It was Col. Gibson who apparently decided to attack out of the Sunken Road although Wright (who had been carried to the Sunken Road on a litter) may have prompted the attack.

We now have the gap from the Mumma Lane junction to the Hagerstown Pike, a distance of 150 yards. If our estimate of 3.6-3.7 men per yard is reasonable, how many men could fit into this space? This gives values of 540 to 560 men. The remnants of Colquitt’s and McRae’s brigade are believed to be in the region of 200 men and at the junction with the Turnpike was Cobb’s brigade thought to be about 350 men. This means that the total number of 550 men is a reasonable estimate and would fit into the gap at a density similar to elsewhere in the Sunken Road.

The assumptions used in this method of considering regimental and brigade frontages seems to be a reasonable one. A density of around 3.5 to 4.0 men per yard seems to be consistent with a regiment formed as a double line, and as both sides utilised the same or similar training manuals this value can be applied to both sides in the conflict. However, this method again signifies that in some specific cases outlined above, the reporting of the number of some of the Confederates brigades at Antietam is questionable.

Finally, what would be the likely number of men that defended the Sunken Road? If we assume a density of 3.6 men per yard for 900 yards gives a total of 3,240 along its entire length. If we subtract the number from Wright’s brigade that arrived later and assume this to be about 440, then the figure falls to 2,800 men. What units make up this number? The remnants of various brigades stretching from the Hagerstown Pike to the Mumma farm lane at 550 men, G.B. Anderson’s brigade of about 1,200 men thereby giving a value of about 1,050 men for Rodes’ brigade. These numbers give a similar troop density right across the sunken road which is not an unreasonable assumption. Even if we allow gaps between each individual regiment and slightly larger gaps between brigades we would attain very similar numbers.
My like button doesn't seem to be sticking. I liked everyone's comments FYI. Just in case they disappear again.
 
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