What was Union General George McClellan's first major operation known as?

Answer 1

The operation George McClellan is most noted for is the Peninsular Campaign of 1862. It was designed to capture the Confederate capital at Richmond, Virginia, but it failed due to his greatly over estimating the strength of Robert E. Lee's army after a series of battles known as the Seven Days. He grew fearful that his Army of the Potomac would be destroyed by Lee, even though the Federals had held there own against the rebels. He withdrew and evacuated his army with the final units leaving Virginia August 26, 1862.
Peninsula campaign

Answer 2

This question may be referring to one of the best ideas that Union General George B. McClellan devised as the commander of the Army of the Potomac. This military "operation" is best known as the Peninsula campaign. McClellan believed that he could outflank the enemy by using Fort Monroe as the place where Union troops could be safely landed. The campaign involved attacking the Confederacy from the east, and landing his forces many miles closer to Richmond, then using a frontal attack beginning in Alexandria, Virginia and marching south with the intention of capturing Richmond Virginia.

Answer 3

There are two military operations that General George B. McClellan is best remembered for. The first was his idea to use Virginia's peninsula geography to capture Richmond, Virginia. Following that, he is most remembered for the Battle of Antietam. There he fought Robert E. Lee's army to a technical draw. McClellan is faulted in that he held back a large number of troops in reserve. If he had used more of his reserve, he might have had a decisive victory.
His superb organization of the Army of the Potomac is the feat most historians cite as his greatest non-battlefield achievement.