Federal Engineering Operations on Petersburg’s Eastern Front, Winter 1864-65

By Paul Luks and Jason Spellman


"The silent and arduous labors of the engineer, upon which depends to such a great extent the success of a campaign, are too apt to be forgotten and overshadowed by the brilliancy of the noble and brave deeds of other arms of the service."
– Bvt. Lt. Col Nathaniel Michler, Chief Engineer, Army of the Potomac

Federal works at Petersburg, August-September 1864

Even at the onset of the Civil War, both armies had taken advantage of defensive opportunities. By 1864, those same uncompromising forces converged again within striking distance of each other. The Overland Campaign showed the value of fieldworks in repelling massive attacks, offering protection against enemy sharpshooters and harassing artillery fire between planned assaults.1 Those lessons were perfected into massive defensive operations carried out just weeks later.

Then attention turned to Petersburg, Va., a vital supply center for the Confederacy, where the Army of the Potomac and Northern Virginia were locked in a stalemate lasting nine months. Historian Earl J. Hess calls the period, “a traditional field campaign with some limited aspects of siege warfare.”2 Field fortifications were a pivotal aspect during the campaign. Trench lines stretched for nearly thirty-five miles across unpredictable terrain between rivers, rail lines, and roads; field obstructions were laden and minefields set between the 2,266-yard path of enemy works; and thousands of soldiers precariously manned the lines, often enduring the harsh elements when not occupying underground shelters.3

To accomplish these feats, the army depended on the corps of Engineers. The department provided technical expertise in the design and construction of complex fortifications.4 Other duties involved establishing corduroy roads and bridges to transport the army, as well as mining and countermining whenever the situation dictated it.

U.S. Engineer detachment, April 1865

Engineer officers were required to supervise large parties of men detached from the front line to provide the necessary labor. For example, Lt. Richard Phillips of the 43rd U.S. Colored Troops was chosen from six others to supervise forty-two soldiers (wielding eighteen axes, two shovels, and six picks) of the brigade’s pioneer company, and messed alongside its commander and staff.5 The Army of the Potomac’s engineer units consisted of:

– U.S. Engineer Battalion: Four companies commanded by Capt. George Mendell.

– Benham’s Volunteer Engineer Brigade: A few remaining volunteer companies of the 15th and 50th New York Engineers that had served in the Army of the Potomac; detailed with Brig. Gen. Henry W. Benham for duty behind-the-lines from the forward supply base at City Point.

– 50th New York Engineers: Battalions of the original regiment assigned to different army corps under the primary command of Lt. Col. Ira Spaulding and the chief topographical engineer. The army’s primary engineer force stationed on the eastern front.

– Elements of the 9th Corps: Line troops of Burnside’s corps detached for engineer duty under its chief engineer, Maj. James St. Clair Morton. Brigade pioneer units replaced these engineer regiments in September 1864.6

Engineers and draughtsmen at army headquarters in Petersburg, Va.

Consulting officers were also on the staff of Lt. Gen. Ulysses S. Grant, including Brig. Gen. John Barnard and senior aide-de-camp, Cyrus Comstock. Both had graduated in the top of their respective classes at West Point and had previously served as chief engineers to the Army of the Potomac.

Inevitable weathering had caused the organic materials of the Petersburg lines to erode by the fall. Federal officers were instructed to inspect the damage and report to division headquarters every week, whereby the chief engineer could recommend repairs. But winter’s bitterness was discouraging to some; Lt. Col. Ira Spaulding directly employed his New Yorkers to stockade several forts after being unable to depend on Second Corps details who were, “affected so much ignorance of the use of tools and showed such a want of interest in the work.”7 And months of occupation had made firewood scarce as the coldness approached. Relative inactivity pervaded along the frontline but probing had occurred throughout the trenches.

Individuals battled emotional stress brought on by stagnant trench warfare. Members of the Ninth Corps were posted on the eastern defenses from the Appomattox River to Fort Davis, living in long barracks with log and clay chimneys. “Rain turned these rat holes into dripping baths,” recalled a member of the 35th Massachusetts. Several brigades did not have proper latrines and sanitation problems contributed to the filthiness as well.8 Known for being particularly dangerous was Fort Sedgwick, later renamed by the troops “Fort Hell.” Albert Twitchell of the Seventh Maine Artillery reported that the enemy fired 75 shells into the fort the entire night and day of December 3rd. He later wrote that the enemy changed to 64-pound mortar shells, although still ineffective to bombproofs and the magazine.9 Gunners watchfully manned their positions twenty-four hours a day. Officers would order the occasional dead interred behind the lines in the division’s burial plot, where each casualty was identified by name, rank, and unit whenever possible.

Gabions with stacked sand bags at Fort Sedgwick

Still, the engineers had projects and objectives that needed to be met. Magazines were fitted with doors, hinges, and locks to keep ordnance stores secure. Others built new field obstructions to be dispersed around the battlefield. William Hopkins of the 7th Rhode Island reported in January that a company squad “had to go about two miles [behind the line], where each corporal and private makes one gabion which constitutes his day’s work... To-day they were back in time for dinner.”10 The 50th New York Engineers made 456 gabions and 20 sections of chevaux-de-frise in one week to be sent to Fort Sedgwick. A company of the same unit also constructed 460 yards of corduroy road in the fort’s covered way.11 Abatis was noticeably absent or mistreated in some sectors, causing the Army of the Potomac to issue Special Order No. 330 that December.12 Under its authorization, posted guards could arrest abusers of the abatis and non-designated shelters too close to the trenches could be destroyed. The intention was not so much to deprive the soldiers of their comforts but make known their vulnerability and the seriousness of uncontrolled enemy raids.

Entrance to a countermine near the Jerusalem Plank Road

Both sides continued to create countermine shafts until the end of the year. At Fort McGilvery, the 50th New York began to dig a system through soil that was so loose that framing supports had to be erected every few inches. A few weeks later, Spaulding gallantly reported their work of 140 feet completed. Southward at Fort Sedgwick, the engineers were fetched to dig three twenty-two foot long shafts with barrels positioned at the end. A string was drawn tightly across the barrel’s tops which could allegedly produce a vibration if nearby digging was felt. Second Corps troops holding the fort had heard constant noises and taken Rebel deserters to reported mining by the enemy (although both sides were known to make false statements). Even a month later, one of Ira Spaulding’s captains reported that he “spent an hour and twenty minutes in the listening gallery and heard noises which might easily be imagined to proceed from miners at work.”13 No further precautions were made however.

Most logistical efforts were focused on the Army Line. The military railroad served as the main spine from which troops could be off-loaded and deployed directly into the trenches. A connection road was built from Hancock’s Station (near the Jerusalem Plank Road) southward to Fort Blaisdell.

Massive operations conducted by the Union army were significant in designing field fortifications that determined the outcome of the Petersburg Campaign. Engineer troops were dedicated architects who contributed to the bold tactics aimed to draw out the enemy from a seemingly stalemated position. Both man and tool worked to achieve the demise of the Confederacy and hasten the last months of the Civil War.


Impression Guidelines

Company D, U.S. Engineer Battalion with department guidon in background

The various companies of the United States Engineers who had been photographed around Petersburg in 1864-65 seem to be dressed in a fairly consistent manner.

The standard Federal issue sack coat and Sky-blue trouser seem to be the norm with the enlisted men and NCOs of the Engineers. This obviously makes sense due to the constant fatigue work that the Engineers would have been doing.

After examining several photographs in respect to headgear, this appears to be the break down. Approximately 2/3 of soldiers are in some form of Federal kepi or Forage cap. Interestingly enough, about a quarter of those are actually kepis (something that is unfortunately under- represented in the hobby). Another third are in civilian slouches, mostly dark colored and about 1 in 10 is devoid of any type of headgear.

A special button was made just for the engineer services but it appears that it was a dress item. It was noticeably larger at 7/8” in diameter and had the seal of the U.S. Engineering services with the phrase “essayons” on it.

In respect to the photographs it appears that sergeants wore the special buttons on their sack coats as one confirmed First Sergeant is wearing them and two potential sergeants have them in one photograph. A surviving yellow trimmed sergeant’s Frock Coat also has the special Engineer buttons down the front.

NCO insignia does appear to be worn about half of the time. The yellow color photographs very dark and similar to the dark blue color and can be difficult to notice at first as well. Even if no chevrons were worn the regulation trouser stripe appears to be affixed about three-quarters of the time in the photographs. It should be noted that even if the regulation insignia is not being worn that some form of differentiating device was worn (i.e. the larger Engineer buttons).

Company B, U.S. Engineer Battalion near Petersburg, Va.

Standard enlisted “US” belts and NCO belts were worn by the Engineers.

It must be remembered that the members of the U.S. Engineers have always been a very proud unit and considered themselves to be elite. Almost every single individual photographed wears the specific brass stamped Castle badge on their headgear. Even in 1864 when the images were taken they took the time to be distinguished in their fatigues.

Many of them also have the brass company letter affixed with the castle. Engineer units were for the most part broken up by company with each individual company being assigned different tasks and places along the line. Hence, it would make sense that some sort of identifying company insignia should be visible. For Forage caps, the brass was applied in a standard manner on the top circular board. On the kepis they were affixed to the front on the cap (the castle being placed over the chip strap and the company letter over it). This makes sense due to the space constraints. Standard brass hat application “rules” seem to apply for the slouch hats.

So in short, enlisted men should wear:

  • Standard Federal Sack Coat and sky blue trousers with brogans. Boots were rare but if worn, they should be under the trousers.
  • Standard US belt and accoutrements
  • Mostly standards regulation shirts but some civilian shirts do appear.
  • Hat brass would be an Engineer Castle and company letter.



  1. Earl J. Hess, In the Trenches at Petersburg: Field Fortifications and Confederate Defeat. (Chapel Hill: University of North Carolina Press, 2009), xiv.
  2. Ibid., xv.
  3. Ibid., xiii.
  4. Hess, 2. Common field fortifications included embrasures, platforms, and revettes for infantry and artillery use. Obstructions such as gabions, abatis, palisades, and wire entanglements were also used.
  5. Ibid., 3.
  6. Companies of pioneers were inconsistently organized within the Army of the Potomac during the Overland and Petersburg Campaigns. By the fall of 1864, two companies were formed in each division and led by either a captain or lieutenant, selected by the brigade’s commanders.
  7. Hess, 200.
  8. Ibid., 209-210.
  9. A.S. Twitchell, History of the Seventh Maine Light Battery, Volunteers in the Great Rebellion. (Boston: E.B. Stillings & Co., 1892), 35-36.
  10. William P. Hopkins, The Seventh Regiment Rhode Island Volunteers in the Civil War, 1862-1865 (Providence: The Providence Press, 1903), 240.
  11. Hess 200, 203.
  12. Ibid., 199-200. Hess points out that some wooden obstructions became firewood out of necessity.
  13. Ibid., 206.