Civil War: The Eastern and Western Theaters


By Gary W. Gallagher, University of Virginia

The United States and the Confederacy enjoyed a quiet period for many months following the First Bull Run, but then the United States commenced a series of offensives in the first half of 1862 that achieved mixed success. There were plans to strike toward Richmond in the eastern theater—east of the Appalachian Mountains—and in the western theater—the great area between the Appalachians and the Mississippi River.

illustration of battle of Shiloh
The bloody battle of Shiloh marked Union’s victory in the West. (Image: Everett Collection/Shutterstock)

Ulysses S. Grant’s Successes in the Western Theater

Henry Hallock, the principal United States commander, put together a brilliant offensive that sought to carry out part of Winfield Scott’s Anaconda Plan. He put in charge of the Tennessee element of this campaign, Ulysses S. Grant, who would prove to be the most important figure on the Union side in the war.

In February and March, Grant captured key southern forts—Henry and Donelson on the Tennessee and Cumberland Rivers. This opened the way to Nashville, which fell soon thereafter—a major Confederate city in that part of Tennessee—and began a slow movement toward northern Mississippi.

The Battle of Shiloh

Grant was having great success here, so he proceeded almost all the way to the Mississippi border, where he ran into a Confederate army unit that was trying to launch a major counteroffensive.

The two forces clashed near the Tennessee-Mississippi border in the backwoods of that part of Tennessee, at a place called Pittsburgh Landing, or Shiloh, and they fought an enormous battle on April 6 and 7, 1862. It was a battle that swayed back and forth; first the Confederates had the advantage, but in the end, Grant carried the day, and drove the Confederate army back in complete defeat.

The losses were enormous at Shiloh—nearly 11,000 Confederate casualties; 13,000 United States casualties. On two days in Shiloh, more Americans were shot than in all of the American wars put together down to that time in United States history, and it chastened the people, both North and South.

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Union Conquering the West

More bad news in the West came quickly to the Confederacy. New Orleans fell at the end of April, the biggest city in the Confederacy.

Memphis fell in early June, so that if one looked at the map in the West, after the first six months of 1862, Hallock and Grant had engineered this enormous string of successes, and they stood poised to accomplish more.

portrait of Robert E. Lee
Robert E. Lee salvaged the Confederacy in the East. (image: Everett Collection/Shutterstock)

Robert E. Lee and the Seven Days Battles

In the East, meanwhile, a principal Union offensive against Richmond had failed by the end of the first half of 1862. The principal Union commander here was a young general named George Brinton McClellan, who decided to strike Richmond by moving a big army by water to the area of Norfolk, and then advancing overland against the Confederate capital.

He got almost to Richmond by early June, but a climactic series of battles at the end of June and in early July thwarted his offensive. Robert E. Lee commanded the opposing army, the Army of Northern Virginia.

In what came to be called the Seven Days battles between June 25 and July 1, 1862, Lee drove McClellan—who had a larger army, with about 100,000 men in McClellan’s army, and about 85,000 in Lee’s—away from Richmond. Casualties were even higher than at Shiloh—with 20,000 Confederate casualties, and 16,000 Union casualties.

Second Battle of Manassas

Lee followed this up with a movement into north central Virginia that resulted in a second battle on the old Manassas battlefield, this one against a Union commander named John Pope. Lee and Jackson, moving quickly and effectively, and achieved a second great victory on the old Manassas battlefield fought at the end of August 1862.

Second Manassas resulted in 25,000 more casualties—about 16,000 on the United States side, and about 9,000 on the Confederate side.

Turn of Tide in the Eastern Theater

Pope’s army retreated into the defenses of Washington, where George B. McClellan lay. McClellan had been recalled from the Virginia peninsula by Abraham Lincoln. There was a good deal of disarray in terms of the federal command there, and Lee and Stonewall Jackson at Manassas Junction were trying to decide what their next move would be.

This was an astonishing turnaround in the eastern theater: From early June, when there was a major United States force within five miles of the Confederate capital in Richmond, to the end of August when there was not any major United States force anywhere near Richmond.

The Confederate army, by contrast, was just a couple of dozen miles outside the capital of Washington, D.C.

Union Win in the West, a Steady Confederacy in the East

Northern morale dropped sharply after the battle of Second Manassas, and Lincoln cast around for what to do in terms of commanders. He shipped Pope off to Minnesota territory to deal with the threat from the Sioux Indians there.

Lincoln turned very reluctantly to George B. McClellan again, to try to re-inspirit the forces that were in Washington. He built the Army of the Potomac in the summer of 1861, and later into the most powerful military force on the North American continent.

McClellan’s organizing skills would come in handy now, trying to bring the army back together after the defeats at the Seven Days battles and at Second Bull Run, trying to get the army into shape to counter whatever Lee might do next.

We see, in the summer of 1862, the United States forces under Grant poised for greater success in the western theater, and Robert E. Lee’s army victorious in the East.

Common Questions about the Eastern and Western Theaters of the Civil War

Q: Which areas in the West did the Union capture?

The Union captured key southern forts, Henry and Donelson on the Tennessee and Cumberland Rivers. This opened the way to Nashville, which fell soon thereafter, and began a slow movement toward northern Mississippi.

Q: What happened in the Seven Days Battle?

In the Seven Days battles, fought between June 25 and July 1, 1862, Robert E. Lee drove George Brinton McClellan—who had a larger army, with about 100,000 men in McClellan’s army, and about 85,000 in Lee’s—away from Richmond.

Q: By mid-1862, which side was winning and where?

By mid-1862, the United States forces under Ulysses S. Grant poised for greater success in the western theater, and Robert E. Lee’s army victorious in the East.

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