Responsibility for fortifications in the pre–Civil War army rested with the Corps of Engineers, the elite of the military establishment. Created initially by the Second Continental Congress in 1779 and renewed in different form by the Congress of the new government in 1794, the corps was institutionalized in its current form in 1802. A separate group of topographical engineers, responsible for mapmaking, was created in the War of 1812 and given its own institutional status in 1838 as the Corps of Topographical Engineers. The U.S. Engineer Department was created immediately after the War of 1812 to serve the administrative...

Although fighting with improvised armies, the field commanders of the Civil War often recognized the value of fortifications. At Big Bethel, First Manassas, and Ball’s Bluff, field fortifications were used in peripheral ways that often had little impact on the outcome of the battles, yet field armies dug in deeper and more widely after each engagement. The capital cities of the opposing sides were ringed with the beginnings of massive earthworks designed to protect the political and administrative centers of the Union and Confederate war efforts. Even along the Atlantic seacoast, fortifications came to play a role in combined operations...

While military operations unfolded in the corridor between Washington, D.C., and Manassas, Union forces also launched successful efforts deep in the western counties of Virginia and along the coastline of North Carolina. Field fortifications were used by both sides as the Federals achieved limited but important victories in these two regions.

The first sustained, deep penetration of Confederate territory began in northwestern Virginia in June 1861. Situated across the Ohio River from free territory, this area was a vulnerable shoulder of the Confederacy. Union troops entered it initially to protect the Baltimore and Ohio Railroad and then enlarged their presence...

The Federals began their long-awaited second drive toward Richmond nearly one year after the fall of Fort Sumter. It would be a massive undertaking, involving more troops than had ever been assembled in a single field army in the country’s history, and would bring a comparable response from the Confederates. The campaign saw the extensive use of fortifications by both sides for offensive as well as defensive purposes, but they never became the key factor in determining the outcome of the campaign. While the Confederates built complex works along the Warwick River during the Yorktown phase of the campaign, all...

When Johnston evacuated the Peninsula, he also abandoned a large number of Confederate forts, water batteries, and defensive lines. The Rebels had expended a great deal of labor for many months perfecting several kinds of earthworks on the Peninsula and along the banks of the James River. Only the Warwick Line proved its mettle in a direct confrontation with McClellan’s army. The engineering skill, time, and labor invested in most of the others were ultimately wasted.

The lower James was defended by numerous works. The Confederates fortified six major positions: Fort Boykin at Day’s Point, Fort Huger at Harden’s Bluff,...

The Seven Days battles saved the Confederate capital for the time being, but McClellan’s large army was still entrenched only twenty miles from the city. Lee refused to accept that his own army had to remain inert in the outskirts of Richmond to guard against another Union thrust. He intended to take the war northward, to enlarge the area of operations, and to confront another Union force, the newly created Army of Virginia under Maj. Gen. John Pope, which was hovering north of the Rappahannock River. This move would shift the focus of the war away from Richmond for some...

Lee went on the defensive after Antietam, and Lincoln replaced McClellan with Ambrose Burnside. The new commander devised a plan that might well have worked. The army was concentrated at Warrenton and would dash for Fredericksburg thirty miles southeast, cross the Rappahannock River, and head for Richmond, another fifty-five miles away. Burnside arranged for supplies and pontoons to be shifted to Fredericksburg in preparation for his move. Maj. Gen. Edwin V. Sumner’s Right Grand Division reached Fredericksburg on November 19, the same day that the leading elements of Lee’s army arrived, but the logistical support was not there. The wharf...

Burnside committed a tragic error of judgment in attacking Lee’s strong position at Fredericksburg. It was compounded by a failed attempt to march around Lee’s left and cross the Rappahannock in January, a good move spoiled by unexpected weather that turned the flanking movement into the infamous Mud March. Burnside was replaced by Maj. Gen. Joseph Hooker on January 26, 1863, and the Army of the Potomac was rejuvenated by improved living conditions, more frequent furloughs, the introduction of corps badges, and Hooker’s infectious optimism. When the spring brought good campaigning weather to Virginia, the Federals were ready for another...

Lee won at Chancellorsville despite having sent away Longstreet and two of his divisions. They were supporting operations in eastern North Carolina and southeastern Virginia that were designed to gather food in this rich agricultural region and put pressure on the Federal garrisons that occupied several towns on the Coastal Plain. The Yankees had established their presence in this region in early 1862 with the Burnside expedition, but they had failed to use it effectively as a springboard to attack vital lines of communication. More important operations in Virginia, most notably McClellan’s drive on Richmond and Lee’s subsequent efforts to...

The ending of the Suffolk campaign allowed Lee to concentrate his army once again. With the addition of Longstreet’s two divisions, he could resume offensive movements given up in the wake of the Maryland campaign. This time Pennsylvania was the goal. Lee hoped to take the scene of operations away from the Rappahannock River, where it had been planted for six months. Gathering food was another consideration, and generally causing havoc on free soil was yet another. The Pennsylvania campaign shook up the North. It was the Confederacy’s biggest incursion into free territory during the war.

Lee planned to enter...

One week after the battle of Gettysburg, Federal troops began a campaign against Charleston, South Carolina, that would be the largest land attack on the defenses of that important city. Not only was it a highly visible symbol, the place where the first shots were fired in the Civil War, but Charleston was an important port for blockade runners. The operations against the city in the summer of 1863 involved extensive fortifications for both offensive and defensive purposes. In fact, Charleston was one of the most heavily fortified cities in America. Confederate authorities had sought to protect the place as...

After the repulse of July 18, Gillmore decided to reduce Wagner by siege approaches and to begin bombarding Sumter at the same time. His position was close enough to the latter work to allow Parrotts to strike the masonry walls. It was believed that the siege approaches might not have to be run all the way to Wagner, for if Sumter’s guns could be dismounted, the navy might be able to run in and cut off boat communication between Charleston and Morris Island. This would accomplish a complete investment of Wagner and starve the garrison into surrender.¹

The result was...

By the time Battery Wagner fell, the Army of the Potomac and the Army of Northern Virginia were resting quietly from the exertions of the Pennsylvania campaign. Lee settled his men around Culpeper Court House in the Piedmont, between the Rappahannock River and the Rapidan River. Meade took position near Warrenton north of the Rappahannock. Both armies used the Orange and Alexandria Railroad as their line of communications, but Meade realized that this area was not the true line of advance toward Richmond. The railroad led southwestward from Alexandria, away from the Confederate capital. This bucolic region between Fredericksburg and...

By the time Plymouth fell, the armies in the East were on the eve of the Overland campaign and its intensive use of field fortifications. The preceding campaigns from Big Bethel to Plymouth were in one sense a preparation for the habitual use of fieldworks in 1864–65. Commanders on many levels relied on breastworks, earthworks, or preexisting features on the battlefield during almost every significant engagement from 1861 through 1864. There was a definite trend toward greater reliance on fortifications, but it was not steady or inevitable.

The evolution of trench warfare was centered, in part, on the problem...