U.S. Corps of Topographical Engineers

Engineers in the Union Army, 1861 - 1865

By Phillip M. Thienel


Part II.  Army of the Potomac


On January 20, 1861, Company A, Corps of Engineers, reported to Washington, D. C., for the purpose of protecting the public buildings, arsenals, and property. In the spring of 1861, the company sailed for Santa Rosa Island, Florida, where it spent five months strengthening Fort Pickens. The company moved to West Point, New York, on September 30, 1861. It remained there only a month, returning to Washington on October 31.

In Washington, Company A was joined by Company B, recruited in Portland, Maine, and Company C, recruited in Boston, Massachusetts, in accordance with the Act of August 3, 1861. The three companies were formed into a provisional battalion under the command of Capt. James C. Duane, Corps of Engineers. One of the first assignments of this Engineer Battalion was the construction of ponton boats. By February 1862, the battalion was ready to test its boats and it went to Sandy Hook, Maryland, where a ponton bridge consisting of forty-one boats totaling 840 feet in length was constructed over the Potomac on February 27. This was the first wooden ponton bridge ever laid across a river for actual military use in the United States. Another ponton bridge, laid across the Shenandoah River east of Harpers Ferry by the Engineer Battalion on March 1, 1862, was used by Pennsylvania troops to cross to Virginia soil. On March 3, the battalion returned to Washington.

The Army of the Potomac was organized in July 1861, with Brig. Gen. J. G. Barnard as the Chief Engineer. Brig. Gen. D. P. Woodbury took command of the newly formed Engineer Brigade, which was composed of the Engineer Battalion and the 15th and 50th New York Volunteer Regiments. During the summer, the 15th New York Volunteers under Col. J. McLeod Murphy and the 50th New York Volunteers under Col. C. B. Stuart had reported to the Army of the Potomac. These two regiments were detailed as engineer regiments and placed under the immediate superintendence of Lt. Col. Barton S. Alexander, Corps of Engineers, in October 1861. The Engineer Brigade spent the winter of 1861-1862 completing its organization and training and constructing bridge equipment.


The Engineer Brigade sailed from Washington for Fort Monroe on March 22, 1862. On April 4 the Engineer Battalion marched to Yorktown and commenced the construction of siege materials. Two ponton bridges were built, one on April 14 over Black Creek, and one on April 19 over Wormsley Creek. Arriving at Yorktown on April 5, 1862, the 15th and 50th Engineer Regiments built roads, bridges, gabions, fascines, and constructed Battery Number 4, a 13-inch mortar, on Moores Plateau. While engaged in engineer operations, the Engineer Brigade constructed, in all, 5,000 yards of roads, three ponton bridges, two log crib-work bridges, and one floating raft bridge over Wormsley Creek. The brigade also established two engineer depots while at Yorktown.Richmond map

And then on May 4, McClellan discovered that Confederate forces had evacuated Yorktown on the night before. In the change in the plan for Franklin's division to land at West Point instead of Gloucester Point, a detachment of the 15th New York Engineer Regiment was detailed to assist in the landing operation. To prevent the artillery pieces from bogging down in the sand on the landing beaches, the detachment p1aced the guns on a decked float made by lashing together two canal barges and ferried the guns and float to the beaches on transports. On arrival at the proper site, the decked barge carrying the guns was floated to the shore where it was connected to the beach by bridges on which the guns were wheeled ashore. Using pontons, 8,000 men were ferried ashore in three hours by the engineer detachment. The barges were then grounded on the beach and lashed together to form a wharf (extending 220 feet into the river) to which transports tied up to unload cargo.

The following day, May 7, the boats moved up the Pamunkey River finally setting up a large engineer depot for the Army of the Potomac at White House. Between May 16 and June 27, 1862, the Engineer Brigade placed over the Chickahominy River twelve bridges which are briefly described.

At Bottoms Bridge on the Chickahominy, where the Williamsburg to Richmond stage road crossed the river, no resistance was offered by the Confederate forces. Companies C and E of the 50th New York Volunteer Engineers put this bridge in order for troops to cross on May 21 and built a new bridge open to troops on May 23. These bridges were 120 feet long. It was reported that seventy-nine regiments, nine hundred wagons, and several batteries of artillery crossed them between sunrise and sunset May 24.

Landing at White Houserailroad bridge on the Richmond and York River Railroad, east of the Chickahominy near Tunstalls Station, was constructed by the 50th, May 19-24. The span was 50 feet and the trestles 21 feet high. Lack of facilities for transporting timber from the woods prevented earlier completion of this bridge. The railroad bridge crossing the Chickahominy had been entirely destroyed by fire. The discovery of a sawmill 3 miles east of the bridge made it possible to bring lumber up on hand cars; and, with the aid of 40 bridge builders from the United States Military Rai1roads, the bridge was completed in about four days.

Sumner's Lower Bridge was constructed 2 miles above the railroad bridge.

Sumner's Upper Bridge was constructed 1 ¼ miles upstream from the lower bridge (site of an "old grapevine" bridge).

I'he Woodbury and Alexander Bridge was constructed 1/4 mile upstream from Sumner's Upper Bridge. The bridge crossed the river at right angles, then made a turn upstream along the northern bank. Its total length was 1,080 feet and, including the corduroyed access roads, it had a length of 1,400 feet. It was constructed entirely upon cribs and stringers strong enough to withstand the floods.

The Woodbury, or Infantry Bridge was built 2 miles above the Woodbury and Alexander Bridge.

The Duane Bridge was a permanent structure upstream from the Woodbury Bridge. It was constructed by the Engineer Battalion that commenced work on June 9, completing the bridge on June 14. It was 1,080 feet long, with a roadway width of 11 feet.

The footbridge was located just above Duane Bridge. It was constructed by the 50th New York Volunteer Engineers over an old beaver dam and only infantry in single file could cross it.

At the site of New Bridge8 miles west of Bottoms Bridge, the Chickahominy was a formidable barrier because it flowed through a swampy area, where it was necessary to provide long approaches of corduroy to the bridges, some of which had to be raised on stringers. At this site the Engineer Battalion placed two ponton bridges and corduroyed the approaches.

The construction of the Lower Trestle Bridge was commenced by the 15th New York Volunteer Engineers on May 31. It was located about 1 mile below New Bridge. At 2:00 a.m. June 2, a bridge 330 feet long consisting of seven trestles and seven ponton boats was completed. The regimental commander, in his report, spoke in the highest terms of the skill, energy, and endurance exhibited by the officers and men on this trestle bridge. He also mentioned their great exposure both in the flooded stream and under enemy fire.

The Upper Trestle Bridgea crib and corduroy structure, was constructed on May 31 by the 50th Engineers 1 mile above New Bridge.


The battle of Mechanicsville on June 26 brought on what the Army of the Potomac termed in its official report "a change in position" which called for a withdrawal down the peninsula on the south side of the Chickahominy. On June 27 the Engineer Brigade put up three bridges in the vicinity of White Oak Bridge, and repaired the corduroy road through the swamp. These bridges were destroyed on June 30, after which the Engineer Brigade proceeded to Haxall's Landing on the James River. After the battle of Malvern Hill, where the Engineer Battalion was posted as infantry, a retreat was ordered to Harrison's Landing farther down on the James River. The Engineer Brigade kept the road open and built redoubts to aid in the defense of the withdrawing army. The records of the Engineer Battalion contain the notation that this was its most disappointing march of the entire war. At Harrison's Landing, on July 5, Company D was activated by the transfer of personnel from the other three companies.

On August 10, 1862, a bridge was ordered constructed at Barrett's Ferry near the mouth of the Chickahominy. The necessary bridge material was at Fort Monroe, approximately 60 miles away by water. The bridge material was loaded on barges and the boats the next day, and towed up river. Company D left overland for Barrett's Ferry, approximately 38 miles. Companies A, B, and C sailed up the river with the rafts on the steamer Matamora, which had brought the Engineer Battalion to Fort Monroe. At daylight on August 13 the tow arrived at Barrett's Ferry. After the material was unloaded, the Engineer Battalion and the 50th New York Volunteer Engineers began at noon to construct the bridge, with Captain Spaulding of the 50th in charge of the western end, Lieutenant Comstock of the Engineer Battalion in charge of the middle section, and Lieutenant Cross of the Engineer Battalion in charge of the eastern end. Work was suspended that night, but at 9:30 a.m. on August 14 the bridge was completed. It was 1,980 feet long, consisting of 5 spans of trestles and 96 boats. The western end was built by successive pontons and the remainder by rafts. Unthreshed wheat stacked in a nearby field was then placed upon the floor boards to prevent undue wear.

The Army of the Potomac with artillery and baggage wagons, except Heintzelman's Corps, crossed this bridge. By 10:00a.m. on August 18 the extreme rear guard of the Army had passed without incident. The bridge was dismantled, and at 3:00 p.m. the bridge material was again in the tow of a steamer, bound for Fort Monroe, accompanied by the Engineer Brigade. Thus ended the Peninsula Campaign. On September 1, 1862, the Engineer Brigade arrived back in Alexandria, Virginia.


On September 7, 1862, the Engineer Brigade was on the march to Antietam, Maryland where, on September 16, the Engineer Battalion constructed two fords across Antietam Creek. The battalion started for Harpers Ferry on September 19, arriving at the Potomac River early on September 21. That night it raised the pontons of a bridge that had been burned and sunk with the recent surrender of Harpers Ferry. Using the salvaged pontons and additional pontons brought up during the night by the 50th New York Volunteer Engineers, a bridge was constructed over the Potomac on September 25. Another bridge of 16 pontons was put across the Shenandoah River on September 27. On October 21, an order was published that enlisted men could transfer from volunteer to regular troops of the Engineer Battalion. By the end of October the strength of the battalion had reached 500 enlisted men.

On October 28, after Antietam, the Army of the Potomac crossed the river into Virginia at Berlin, Maryland, east of Harpers Ferry, over a 61-ponton bridge constructed on October 24. The Engineer Battalion left the Harpers Ferry area on November 3, arriving at Warrenton, Virginia, five days later. The Engineer Brigade proceeded to Falmouth, Virginia, to construct bridges over the Rappahannock River for an attack on Fredericksburg. The brigade formed on the north bank of the river on December 10.


Orders were issued on December 10, 1862, that two bridges would be constructed over the Rappahannock at the upper (western) end of Fredericksburg; one at the lower (eastern) end of Fredericksburg; and two a mile below the lower bridge. The distance between the two outside bridges was 2 miles. The lowest bridge was to be built by the battalion, and the 15th and 50th Engineers were to construct the other four bridges. Orders stated that four bridge trains would arrive at 3:00 a.m. December 11, and that the bridges would be finished by daylight.

It was not until 10:00 a.m. that the battalion completed its bridge at Franklins Crossing, about a mile below Fredericksburg. Major Magruder and the 15th completed the bridge at the lower end of the town by 9:00 a.m. in spite of disrupting enemy fire. The 15th then assisted in the construction of the other bridges. Major Spaulding of the 50th was in charge of constructing the two bridges at the upper end of Fredericksburg and one of the bridges a mile below the town. One of the extreme lower and one of the upper bridges were two-thirds finished at 6:00 a.m. when Confederate troops opened fire, killing Captain Perkins of the 50th and holding up the completion of the bridges. The engineers had no weapons with which to return the fire. General Woodbury, commander of the Engineer Brigade, led 80 volunteers from the 8th Connecticut Infantry to the area under fire. When the fog which had engulfed the valley lifted, Union artillery opened fire and assisted in completely subduing the Confederate fire. Then 50 men rowed across the river and routed the Confederates. The five bridges were completed without further opposition. Later an additional bridge was constructed below Fredericksburg. Each of the three bridges opposite the town were 400 feet long; and the three bridges below the town were 400, 420, and 440 feet long, respectively. With the failure of the campaign and the withdrawal of the Union forces to the northern bank of the Rappahannock River, the bridges were dismantled on December 16 by the brigade.


Sixteen bridges were constructed by the Engineer Brigade over, and then removed from, the Rappahannock River during the period April 28 to May 28, 1863. This included the Battle of Chancellorsville, May 2 to 4, 1863.


On June 18, after the term of enlistment of a large number of volunteers had expired, the three-year men in the 15th New York Volunteer Engineers were reorganized into three companies. The Engineer Brigade had already begun its march on Gettysburg the day before. Rafts with the bridge pontons fastened on top were placed in the Chesapeake and Ohio canal for towing up to the battle area. A bridge was constructed over the Potomac at Edwards Ferry, east of Leesburg, Virginia, by the brigade. It was 1,340 feet in length, with 64 boats and 3 crib trestles. Companies A and C of the Engineer Battalion constructed a bridge of 11 boats across the mouth of Goose Creek nearby. A second ponton bridge was erected at Edwards Ferry on June 25 by the 50th Engineers. By June 27 the army was on the Maryland side of the river and the two bridges had been taken up.

On July 11 the Engineer Battalion constructed a bridge of 4 cribs at Antietam Creek. The battalion was then ordered to Sharpsburg, Maryland, on July 13, but on July 15, while on the march, it was ordered to make a forced march to Harpers Ferry. Arriving there, the battalion constructed a bridge of 60 pontons over the Potomac River on July 18 at Berlin, Maryland. Then on July 19, the Engineer Brigade returned to Virginia soil. This was the third time the engineers had helped troops of the Army of the Potomac to cross the Potomac onto Virginia soil. Oddly enough, the Engineer Brigade did not directly participate in the Gettysburg campaign, and, according to the records, did not march on Pennsylvania soil. With the termination of the Gettysburg campaign, the brigade returned to Rappahannock Station on the familiar banks of the Rappahannock River.


In the summer of 1863, the Army of the Potomac crossed to the south side of the Rappahannock; but on October 13 it was forced to re-cross to the north side of the river. For these movements, the Engineer Brigade constructed bridges at Kelly's Ford, Rappahannock Station. and Beverly Ford, taking them up after the return to the north bank at which time the railroad bridge at Rappahannock Station was destroyed. The Brigade then went into camp at Centreville, Virginia. During the latter part of October and the early part of November, the Army of the Potomac marched back to the Rappahannock River making repeated efforts to cross it. Bridges were constructed at Kelly's Ford, enabling the army to march to Brandy Station and Culpepper. Efforts were then made to cross the Rapidan River and for this purpose the brigade constructed bridges at Germanna Ford and Jacobs Ford, but again the army was forced to withdraw to the north bank of the Rapidan.


With the arrival of spring in 1864, the Army of the Potomac successfully crossed to the south side of the Rapidan River on May 4. At Culpepper Mine Ford, the 50th Engineers constructed a bridge. On May 5 the battle of the Wilderness started and on May 7 the Engineer Battalion and the 50th fought as infantry. The march began to Spottsylvania that night and the battle of Spottsylvania Court House was fought May 8. The army crossed the Po River on May 10 on crib bridges constructed by the Engineer Battalion.


Now the campaign in Virginia went forward in earnest and the engineers were right in the forefront. The Ny River was crossed at Guinea Station. The 50th laid a ponton bridge over the North Ana River at Jericho. On May 28 the army crossed the Pamunkey River at Huntleys, 4 miles northwest of Hanover Town, on bridges laid by the 50th Engineers. June 1 marked the opening of the Battle of Cold Harbor. Here the engineers constructed rifle pits, mines, roads, and defense works. Again the Engineer Brigade constructed bridges over the Chickahominy. Two bridges were laid at Forge Mill, east of White Oak Swamp, by the 50th Engineers. After crossing this bridge the army marched to Charles City Court House. By June 14, 1864, the Army of the Potomac was again maneuvering for battle on the north bank of the James River. In this march from the Rappahannock-Rapidan area the volunteer engineer regiments constructed 38 bridges, with a total length of 6,458 feet.


At the James, the Engineer Brigade made contact with the 1st New York Volunteer Engineers of the Army of the James. In building a bridge in the slime and mud of the James River, an abutment of trestle work 200 feet long was constructed by the Engineer Battalion out to the deep water after which the 1st New York Engineers took up the work, with the Engineer Battalion going to the far shore for duty. The 15th and 50th Engineers arrived at the bridge site shortly thereafter and took over the task of completing the bridge. Materials for the bridge were brought up the river by boat. By midnight the bridge was ready to carry traffic. It took eight hours to build and it consisted of 101 pontons and 200 feet of trestle work, totaling 2,200 feet. In the channel, schooners anchored fore and aft held the bridge in position by hawsers. A draw in the center of the bridge accommodated the gunboats passing up and down the river. From June 14-15 nearly the entire army as well as 3,000 beef cattle and 50 miles of wagons crossed to the south side of the James River without mishap. The bridge was dismantled on June 18 by the 15th Engineers and taken to City Point, Virginia. Other bridges constructed in the area were one over the James at James Landing on June 20; a 36-boat bridge at Broadway Landing, on the Appomattox by Company D of the 15th on July 26; and one by Company B of the 15th at Jones Landing across the James. These operations placed troops nearer the defense works around Richmond.


With the army across the James, the Engineer Battalion marched on June 16 to Prince George Court House and thence to Petersburg. On July 1, 1864, Company A of the battalion assisted in building the famous mine under Elliots Salient and prepared the covered way to the entrance. The Engineer Brigade was continually employed along the siege lines on defensive works, forts, and in the construction of gabions, fascines, gun batteries, and rifle pits. The battle of the Crater occurred on July 30. To the Engineer Battalion, held in readiness to spearhead the assault after the explosion of the mine, the outcome was a sad disappointment. From June 22-30 one battalion of the 50th New York Volunteer Engineers was in the pits at Petersburg as infantry. The regiment also built a 140-foot countermine at Fort McGilvery and constructed a bridge on the Nottoway River.


In the spring of 1865 the breakthrough at Petersburg occurred, and on March 29, 1865, the army was set in motion. It was the duty of the Engineer Battalion to keep the roads in repair. On March 31 the battalion put a crib bridge over Gravelly Run which troops of the 5th Corps used on April 1, hastening to aid Sheridan at Five Forks. Richmond and Petersburg were evacuated on April 2. At the battle of Sailors Creek, April 5, the engineers recovered the dead and wounded from the battlefield. By April 8, the Engineer Battalion had marched beyond Farmville. It stood guard at General Headquarters when the surrender took place at Appomattox. The battalion returned to City Point, and on May 4 crossed to the north bank of the James River at Aikens Point on the march to Richmond from which place it proceeded to Fairfax Court House, where it arrived on May 13 and established its camp. It passed in review on May 23 with the Army of the Potomac in Washington, D.C.

Following the evacuation of Petersburg, the 15th New York Volunteer Engineers were brought in to repair three damaged bridges on the Appomattox River. By April 6, 1865, the 50th New York Volunteer Engineers were within 6 miles of Burkeville. This regiment opened and repaired roads for troops on the march towards Appomattox. It was ordered on April 7 to bring bridge equipage to Farmville. The end at Appomattox meant the return march for the 15th and 50th New York Volunteer Engineers, and on May 5 they reached Richmond, parading there the next day. On May 23 they participated in the Grand Review for the victorious Union Army in Washington, D. C.






Copyright © 1995 -
U S Corps of Topographical Engineers
This may be used for non-commercial
purposes with appropriate attribution.