Major General Joseph Hooker had approximately 134,000 troops in the Army of the Potomac on March 31, 1863. He outnumbered the Confederate Army of Northern Virginia by a comfortable margin.
potomac river
potomac river
General Robert E. Lee planned and led the Army of Northern Virginia across the Potomac River and into Maryland. On September 17, 1862, his army the Union's Army of the Potomac would engage each other in the Battle of Antietam.
Prodded by President Lincoln, Major General George B. McClellan finally made a move into Virginia. On October 30, 1862, McClellan crossed the Potomac River and moved southwards in the general direction of Gordonsville. There the railroads of the Orange and Alexandria connected with the Virginia Central. McClellan planned to cut Lee's communication lines with Richmond.
General George Meade needed to halt Lee's invasion of the North before it threatened Harrisburg, Pennsylvania, Philadelphia, Baltimore, or Washington DC. He forced Robert E. Lee to fight a battle that Lee had never planned for. The Army of the Potomac was successful in forcing Lee to retreat back to Virginia.
General William S. Rosencrans devised a Winter offensive into Virginia late in 1861. He believed that he could capture the Virginia town of Manchester by turning the Confederates at Manassas. He traveled to Washington DC to gain permission for this plan from his General in Chief, George B. McClellan. McClellan rejected the idea as too risky and it might force the Confederates in a position not expected as he planned for the Peninsula campaign.
General George McClellan moved his troops to Virginia primarily via a series of carefully planned and executed maneuvers, utilizing the extensive rail networks and rivers for transportation. He organized his forces into the Army of the Potomac and ensured logistical support for the movement, which included the use of steamships and railroads to transport troops and supplies efficiently. McClellan's cautious approach and emphasis on organization aimed to prepare his army for the challenges ahead in the Virginia theater during the Civil War.
By May of 1861, Union troops crossed the Potomac River and took over Alexandria, Virginia. They met little resistance and planned to use Alexandria as a bas for beginning military operations against Virginia.
Confederate General Robert E. Lee knew he was clearly outnumbered as the Battle of Antietam was about to begin. To compensate for the large disparity in troop strength. Lee decided to use the battle tactic of tactical defense. With the understanding that he could not mount any kind of offensive and being clear that the Army of the Potomac, led by General George B. McClellan, a well planned defense was Lee's best alternative to escape losing his army.
After the poorly planned attack on Fredericksburg during the American Civil War, President Abraham Lincoln replaced Union General Ambrose Burnside as the commander of the Army of the Potomac. Burnside's failed strategy and high casualties led to the decision to find a new leader for the Union forces.
There was no question that newly appointed General Burnside would make an offensive move into Virginia. With that said, military theorist Clausewitz had made it clear that more often than not, the offensive army is destroyed not so much by a tactical defense, but self destructed by a poorly and recklessly designed assault on enemy positions.That is exactly what Burnside did, although he might have made a better decision if he knew how many Confederate troops he planned to attack at Fredericksburg. Burnside believed that only one wing of Lee's army was entrenched in the bluffs above Fredericksburg. Burnside did not realize that Lee's entire army was waiting for him at Fredericksburg. Burnsides relentless frontal assaults on Lee's army cost him 12,000 troops. Virginia began to be a target that would take more than frontal assaults in order for the Union to control the state.
Union general Halleck planned the assault on Corinth. Indeed the city was evacuated by the Confederates before the assault.