U.S. Corps of Topographical Engineers

Engineers in the Union Army, 1861 - 1865

By Phillip M. Thienel

Part IV.  The Engineers in the West


Among the numerous engineer organizations employed in the Union invasions via the Mississippi, Tennessee, and Cumberland Rivers, were the 1st Michigan Engineers and Mechanics Regiment j the 1st Missouri Engineers; the Independent Company of Engineers and Mechanics, Kentucky; 1st Veteran Volunteer Engineer Regiment; and 1st to 5th Regiments of Engineers, Corps d' Afrique, redesignated 95th to 99th Infantry, but retained on engineer duties. In the summer of 1864 the 1st Michigan Engineers and Mechanics Regiment and 1st Missouri Engineers were transferred from the Army of the Ohio and Army of the Mississippi, respectively, to General Sherman's Military Division of the Mississippi for duty in the Georgia and Carolina campaigns. Before being transferred to General Sherman's command they had established an enviable record as engineer regiments and had performed unique engineering feats.


This regiment, Col. William P. Innes commanding, underwent its first war experience in the battle of Logans Cross Roads, Kentucky, on December 19, 1861. In addition to engineer duty, the regiment guarded the Union Army camp and, after the battle, collected and buried the dead of both sides and moved the wounded to battlefield hospitals.

The regiment participated in the siege of Corinth, Mississippi, in April 1862, corduroying roads and constructing bridges on Bear Creek and Lick Creek. During the summer of 1862, it was employed on rebuilding the Memphis and Charleston, the Tennessee-Alabama, the Nashville and Chattanooga, and the Louisville and Nashville railroads. Across Elk River, the regiment constructed a railroad bridge 700 feet long and 58 feet high in 20 feet of water. Four companies of engineers worked on this bridge, the heaviest one constructed by the regiment. Also constructed were two bridges over Richmond Creek, one 375 feet long and 28 feet high and the other 300 feet long and 30 feet high. The regiment cleared obstructions from the railroad tunnels and built stockades for the protection of railroad bridges. The railroad work permitted use of the roads to Stevenson, Alabama, and made rails available to the Army of the Ohio as it moved east to Chattanooga. At Bridgeport, Alabama, the regiment constructed pontons for a bridge to cross the Tennessee River for the march of the Army of the Ohio on Chattanooga.

In the summer of 1863, the regiment participated in the Tullahoma campaign; it opened the railroad from Murfreesborough to Tullahoma; constructed a bridge 350 feet long over Duck River Crossing; chopped out and constructed 1 ½ miles of new road leading to Tullahoma; and then rebuilt two bridges on the McMinnville Railroad, one 120 feet long and the other 55 feet long.

In the battles around Chattanooga, the regiment assisted troops from the Army of the Cumberland in amphibious landings. On the night of October 26, 1863, the regiment carried troops in 52 boats, totaling 1,600 men, 9 miles down the Tennessee River below Chattanooga to Browns Ferry. It was a cloudy night and in gliding down the river the boats passed by Lookout Mountain where the enemy was entrenched. After quietly landing, these troops surprised the enemy pickets and were able to hold on to the shoreline. The engineers then went to the right bank of the river and picked up additional troops. Without confusion and under enemy fire, 5,000 troops were ferried across the Tennessee River to the south bank. At daylight, the engineers constructed a bridge across the river at this point to pass over additional troops and supplies.

By November 17 these same engineers were prepared for another amphibious landing east of Chattanooga at the junction of the Chickamauga and Tennessee Rivers, in the campaign to take Missionary Ridge. The 116 boats used in the landing were in the river and ready to go on November 20. A successful landing, approximately 8 miles east of Chattanooga, was made on the south bank of the Tennessee. On November 24 at 5:00 a.m. the regiment began building a ponton bridge at this point over which 8,000 troops moved across the river to the line of battle. The bridge, 1,400 feet long, was made up of pontons constructed entirely by the regiment. It also placed another bridge across the Chickamauga River and two across Chattanooga Creek.

On January 1, 1863, the regiment became the sole engineer organization in the war to engage and best the Confederate forces in combat entirely dependent upon its own manpower and firepower. This episode occurred at LaVergne, Tennessee, on the Murfreesborough Pike southeast of Nashville. General Rosecrans, commander of the Army of the Cumberland, reported that the 1st Michigan Engineers and Mechanics Regiment, under the command of Colonel Innes, fought behind a slight protection of wagons and brush and gallantly repulsed a charge from more than ten times their number of General Joseph Wheeler's cavalry. Colonel Innes reported: "On January 1, 1863 my command of 391 men was attacked by a rebel force of cavalry. The force plundered 30 of our wagons. There were seven charges against us but my gallant men repulsed them.

"At 5 the enemy sent in a flag of truce demanding our surrender. I refused. Then they asked for a truce to bury their dead. I refused. I sent for help from 10th Ohio Infantry."

However, Wheeler's forces withdrew before additional Union forces could join the fray. Casualties for the engineers were two killed, nine wounded, five missing; and the regiment buried six and took six wounded Confederates to the hospital.


Beginning its military operations at New Madrid, Missouri, and Island No. 10 in the Mississippi River (two remaining Confederate strong points on the river) the regiment, under Col. Joshua W. Bissell, constructed the siege works around New Madrid (Figure 3) in March 1862. After the withdrawal of the Confederates from New Madrid, the regiment began constructing the siege works for Island No. 10. Even though the Union forces occupied New Madrid, the Confederate forces on Island No. 10 prevented the passage of boats down the Mississippi River to New Madrid.

New Madrid and Island 10To find a means of opening river traffic, Colonel Bissell reconnoitered the area and determined that a road across the swamp was impracticable, but that a canal could be dug through the marshland for small steamers. It was not found practicable to make the canal deep enough for the gunboats within a reasonable time. Even so, the work was a prodigiously laborious job. The canal was 12 miles long, 6 miles of it through heavy timber. A passage 50 feet wide was made through the swamp by sawing off trees of large size 4 ½ feet under water. The construction work, prosecuted for nineteen days with untiring energy, was completed April 4, 1862. General Pope said in his report: "Full of resource, untiring, and determined, he [Colonel Bissell] labored night and day, and [the 1st Missouri Engineers] completed work which will be a monument of enterprise and skill." On April 2, 1862, Assistant Secretary of War Thomas A. Scott inspected the canal and reported to Secretary of War Stanton that it was a "herculean job."

In October 1862 the regiment was assigned to the Army of West Tennessee with which it participated in the battle of Corinth. It rebuilt bridges, repaired railroad tracks, and cleared trees which had been felled in the road by the Confederates to slow the march of the Union Army..

In the summer of 1864 the Army of the Ohio, Army of the Cumberland, and Army of the Tennessee were brought together by General Sherman to form the Military Division of the Mississippi and Capt. O. M. Poe, Corps of Engineers, was appointed engineer of the combined force. At the time, the 1st Missouri Engineers and the 1st Michigan Engineers and Mechanics Regiment were the only engineer units with the force. They were engaged primarily in the maintenance and repair of railroads in Tennessee that formed the lines of supply. To equalize the engineer forces, one of the engineer regiments (the 1st Missouri Engineers) was transferred from the Army of the Cumberland to the Army of the Tennessee, and the pioneer corps within the Army of the Ohio was assigned its engineer functions. The Army of the Cumberland carried 800 feet of ponton bridging and the Army of the Tennessee, 600 feet. This equipment was the canvas bateau type. To preserve the pontons, a policy was established that a trestle bridge was to replace a ponton bridge if a bridge were required for more than 48 hours.

The movements of the Military Division of the Mississippi comprised: the Atlanta campaign, July 1 to September 2, 1864; the Savannah campaign, September 3, 1864, to January 25, 1865; the march from Savannah to Goldsboro, North Carolina, January 25 to March 22, 1865; and the march from Goldsboro to Washington, D. C.


During the march of the army from the Chattanooga area to Kenesaw Mountain, the work of the engineers consisted of reconnaissance, road making, and bridge building. On the night of July 2-3 the Confederate troops evacuated Kenesaw Mountain, permitting Sherman to move to the Chattahoochee River. The engineers placed bridges over this river at Phillips Ferry, Turner Ferry, and Sandtown in the early part of August. These bridges enabled the army to move across the Chattahoochee River and, by September 2, to march into Atlanta. During this campaign, the engineers constructed the following works: ten ponton bridges across the Chattahoochee River, averaging 350 feet in length; seven trestle bridges over the Chattahoochee River from material cut from the riverbank (five were double track and two were single track bridges, averaging 350 feet in length); 50 miles of infantry parapet with a corresponding length of artillery epaulement; and six bending railsbridges over Peach Tree Creek, averaging 80 feet each; five bridges over Flint River, averaging 80 feet each.

Upon the occupation of Atlanta, the two engineer regiments were engaged in constructing a new line of fortifications around the city until November 1 when work was suspended.

Before leaving Atlanta on November 15, 1864, General Sherman directed the army engineer to destroy all the railroads and their property and all storehouses, machine shops, mills, and factories within the lines of, the Confederate defenses at Atlanta. Under the supervision of Captain Poe, the two engineer regiments carried out the demolitions. About 10 miles of railroad track were destroyed by burning the ties and twisting the rails. Buildings were first burned and then the walls demolished. For military purposes, the city of Atlanta ceased to exist; no railroad was able to take a train into or out of the city.

In his report of the Atlanta campaign, Captain Poe wrote: "On the march, the engineer department was constantly engaged in the most arduous duties, repairing roads, building bridges, destroying railroads, and all other matters coming within our province. I think I can safely say the engineers are popular in this army and enjoy the esteem and confidence of all commanders. The labor performed was immense.

"The ponton trains were frequently used, but never failed. Their efficiency became a subject of remark throughout the army. The ponton trains of the 1st Missouri Engineers were hauled on wagons all the way from Nashville, Tennessee, from where they started on April 1 and are still in efficient condition -- strong evidence of the durability of the canvas ponton train."


The engineer organization for the march to Savannah included the same two regiments, the 1st Michigan Engineers and Mechanics Regiment, assigned to Sherman's headquarters, and the 1st Missouri Engineers in charge of ponton trains and assigned to the Army of the Tennessee. Pioneer troops consisted of 100 men from each division in the left wing of the army and 100 men and 70 negroes from each division in the right wing of the army -- a total force of 2,775 engineers and 1,800 pioneers.

The Michigan Engineers had a train of 50 wagons, of which 20 were loaded with 1,500 axes, 1,500 shovels, 700 picks, 200 hatchets, 100 hooks to twist railroad iron, and ample carpenter and bridge building tools. The Missouri Engineers had ponton bridge equipage totaling 580 feet.

During the march from Atlanta to Savannah fifteen ponton bridges were constructed, totaling 3,460 feet, before the army arrived in front of Savannah on December 10. The Missouri Engineers rebuilt the bridge over the Ogeechee which enabled the army to cross on December 13 and march on Fort McAllister.


Between January 25 and March 22, 1865, the army was on the march from Savannah to Goldsboro, North Carolina. The Michigan Engineers and the Missouri Engineers carried pontons because of the swampy nature of the route. To cross the Savannah River the engineers constructed at Sister Ferry 700 feet of ponton bridging and 1,000 feet of trestle bridging. By February 1, the army had completed crossing over these bridges.

On February 4, the army crossed the swamp at Bufords Bridge. In one mile of swamp some twenty two bridges were constructed, each bridge averaging 25 feet in length. Above Columbia, South Carolina, a bridge was constructed over the Broad River. On February 19, the Michigan Engineers destroyed all railroad shops, depots, and the city gas works in Columbia, and the Columbia and Charlotte railroad from Columbia northward.

Reaching the Catawba River on February 23 the army completed the crossing on the 27th. Rough waters swept away 200 feet of the 700 feet of bridging. The army arrived at Fayetteville on March 11, where the Michigan Engineers destroyed the United States Arsenal and its machinery.

As the march continued, two ponton bridges were constructed on March 13 over the Cape Fear River and taken up two days later. At Goldsboro four ponton bridges were constructed over the Neuse. The arrival at Goldsboro on March 21 terminated a 500 mile march in 60 days through swampland. This march route involved immense engineer work including 400 miles of corduroy roads.


From Goldsboro the army marched through Raleigh, North Carolina, to Washington, D. C., where on May 24, 1865, the Army of the Tennessee passed in review in the capital city. Immediately following General Sherman in the parade were the 1st Michigan Engineers and Mechanics Regiment and the 1st Missouri Engineers.

In his final report, Captain Poe stated: "Every army corps ought to be provided with one good engineer regiment that ought to be capable of doing anything required. As examples of such regiments, I will refer to the two which accompanied us. I never called for workmen to work in wood, metal or stone but good mechanics were not at once forthcoming."


The work performed by the engineer troops and troops under the engineer, Military Division of the Mississippi, was as shown in the Table.







Atlanta Campaign






Savannah Campaign












Washington, DC


















The five Negro regiments, 95th to 99th Infantry, assigned to engineer duty, were employed on the Gulf Coast. The 95th participated in the siege of Port Hudson, Louisiana, in May and June 1863, carrying fascines, entrenching tools, and sandbags to the gun positions. It also participated in the Sabine Pass Expedition and the Brazos Island landings later in the year. The 96th took part in the expedition to Matagorda Bay, Texas, on December 5, 1863, and constructed fortifications at Port Cavallo. With the 97th it served in the Mobile, Alabama, Campaign, the two regiments being stationed at Starke's Landing, Alabama, until the surrender of Spanish Fort and Fort Blakely in Mobile Bay. At this base they constructed six wharves from 300 to 500 feet in length, repaired one for the use of the sick and wounded, moved all supplies inland, and kept roads in repair, The 98th served at Brashear City, Louisiana, and the 99th at Plaquemine and Morganza, Louisiana, and Tortuga, Florida.


This engineer company performed numerous engineer tasks on the Mississippi River, especially in and around the city of Vicksburg. On March 30, 1863, the company marched to Richmond, Louisiana, in the advance of the army that was to attempt to take Vicksburg from the rear. It built a floating bridge 300 feet long over Bayou Roundaway on April 1 within 24 hours. On April 5 it prepared a casemate for a 12 pound howitzer fastened to a flatboat and the Union forces used it to advance upon Carthage, driving the Confederate forces 5 miles down the Mississippi River.

On April 19 the company received orders to construct a bridge 780 feet long across Bayou Vedell, 12 miles below Carthage. This job was completed in 14 hours. Another bridge 250 feet long was constructed across Negro Bayou.

By means of flatboats, 150 tons of ammunition were transported to the Mississippi River from Richmond, Louisiana. Then the flatboats were used by this company to construct a bridge 630 feet long over Mound Bayou which was completed on April 26. At the battle of Big Black River, the company constructed a bridge 200 feet in length over the river.

After participating in the battle of Vicksburg, the company was ordered in July to New Orleans, Louisiana, where it spent the summer constructing water wagons and canvas pontons. In November it embarked for Brazos Santiago, Texas. While in Texas it constructed bridges, hospitals, signal stations, wharves, and defense works. The company was transferred to Alexandria, Louisiana in April 1864 where it assisted in constructing the "Great Dam across the Red River." This was an effort by Union Army engineers to raise the water level in the river to float naval gunboats that were grounded in the river. The company was ordered to Louisville, Kentucky, in November 1864 where it was mustered out of service because of the expiration of its term.


This engineer regiment was organized in the summer of 1864 at Chattanooga, Tennessee. It never took the field in combat operations. However, in and about Chattanooga it constructed earthworks and revetments of Forts Creighton, Phelps, Putnam; and Redoubt Jones, and was engaged in such activities as building reserve magazines, the water works, and hauling and rafting lumber.


The foregoing are the outstanding achievements of the engineer units in the Union Army. It seems incredible that one Regular Army Engineer Battalion and two Volunteer Engineer Companies and eleven Volunteer Engineer Regiments could build ponton and trestle bridges, fortifications, siege works, canals, and mines, and perform numerous other engineer tasks for the entire Union Army in the vast geographical expanse of the battlefield. But through a high sense of personal devotion to duty these accomplishments were inscribed in the official records. These engineers performed the same functions that engineers are performing today, except that the stress, as it was in the Civil War, is placed upon adapting military engineering techniques to the current methods of warfare.







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