Civil War Fortifications

This entry is part 8 of 10 in the series The Organization of the Armies
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Civil War Fortifications

Emplacements at PetersburgIn many respects the American Civil War was one of the first modern wars fought. During the war both sides devised better and more efficient methods to conduct war. As the war progressed through the years fortifications became increasingly more important for both armies. One must understand that many of the officers in higher commands on both sides were either West Point, The Citadel (SC) or Virginia Military Institute-trained engineers who were schooled in building forts, defensive lines and railroads.

The early years of the Civil War were marked by battles of maneuver by both sides. The Confederates were much better at this and won many of the battles in 1861 and 1862. Fredericksburg marked the first major battle where there were frontal assaults against fortified positions. At the time it was an anomaly among the battles of maneuvering units. Vicksburg was a traditional siege but again was followed by maneuver battles. The years of 1864-1865 were years of siege and fortifications.

At the Battle of Franklin Confederate General John Bell Hood wrecked his army by ordering a series of frontal assaults against the prepared Federal defenses around the city of Franklin. At Franklin the Confederates lost almost 3 times as many men as the Federal forces. The Federal defenses consisted of a ditch about 4 feet wide and 2-3 feet deep. Then there was a wall of dirt and wooden fence rails 4 feet above ground level with a ditch behind the wall where the defenders could stand and fire their weapons through gaps in the fence rails. One portion of the line had a near-impenetrable abatis of Osage-orange shrubs. The defenses were manned by the veteran soldiers of the Army of the Cumberland and the Army of the Ohio.

During the Overland Campaign in May-June 1864 both sides used a variety of defenses to protect their men from the lethal massed rifle fire of the enemy. Most of these were quickly built defensive positions that were used for a day or two. At Spotsylvania Court House the defensive lines were more permanent since that engagement lasted several weeks. The Confederate defensive positions are still visible almost 150 years later. The Battle of Cold Harbor marked the beginning of permanent siege lines that continued at Petersburg for all but the last two weeks of the war.

On the very basic level soldiers of both armies could throw up a earthworks defensive line rather quickly. Each unit along a line would dig a broadAbatis trench. On the side facing the enemy there would be a solid wall of logs. In front of the wall would be a ditch 6 feet deep and 10 feet wide. The earth from the ditch would be used to strengthen the wall until it was 6 to 8 feet high and perhaps 12 feet thick. On top of this embankment the soldiers would stack logs or sandbags with slits or loopholes for firing. Behind the wall would be a step to enable troops to man the wall. On the more permanent defensive lines, covered ways would be built to protect soldiers who were coming and going from the rear.

In front of the trench lines, maybe 50 or 100 yards forward, the defenders built a series of obstacles called abatis. In the Civil War these were usually constructed using trees. They were positioned so that their bushy ends faced the enemy. Their branches were sharpened and the butts were embedded in trenches to prevent the enemy soldiers from dislodging them.  They were lashed together to create an impassable barrier. In some areas there were several rows of these. Usually, there were lanes cut through them to enable pickets to go through them and man their forward positions.

Cheval de frise at PetersburgSometimes the abatis was supplemented by chevaux-de-frise. This defensive obstacle was a series of heavy logs with sharpened stakes inserted in them. The logs were then chained or roped together to present a solid barrier.

Both sides positioned forts on every hill or knob along the line. A fort (video) was generally a square enclosure of logs and earth that held one or more pieces of artillery. The artillery was positioned in such a way that they had a clear field of fire covering all of the approaches to the defensive line. Behind the lines both armies dug pits to hold mortars. All of the defensive positions were surrounded by bombproofs (video) where men could take cover during enemy bombardments. They were simply square holes in the ground that were roofed over with logs and earth. In most cases the Confederate lines and the Federal lines mirrored each other.

In 1863 U.S. Grant and his army of the Tennessee besieged the fortress city of Vicksburg from May 18 to July 4, 1864. The Confederate defenses ran for 6.5 miles around the city and consisted of gun pits, trenches, redoubtslunettes and forts. The city was on a bluff overlooking the Mississippi River which gave the defenders an advantage since the Federal attackers had to move uphill. The city was surrounded by a number of large defensive positions that were equipped with artillery. Initially, Grant tried to rush the city but when that failed he was forced to settle in to a siege. Eventually, Grant’s army reinforced with the addition of 22,000 encircled the city. Vicksburg was doomed. On July 4th Lt. Gen. John C. Pemberton, the Confederate commander, was forced to surrender.

During the siege of Petersburg, the art of fortifications was taken to a higher level. The lines around the city were 35 miles long. The Federal forceArtillery positions numbered as many as 125,000 men at times while the Confederate force averaged around 52,000. Some of the most elaborate defenses ever built in North America were built at Petersburg. The siege lasted almost 10 months.

The Federal army suffered over 11,000 casualties while the Confederates lost about 4,000. In the end the Confederate lines were broken in three places and Lee withdraw his army to the west in a vain attempt to link up with General Joseph Johnston’s army in North Carolina. Two weeks later Robert E. Lee surrendered the remnant of his once-proud Army of Northern Virginia at Appomattox Court House.

Series Navigation<< The Union Army and the RailroadsComparing Grant and Lee >>The Confederate States Army Structure and Ranks >>

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