The Battle of Yorktown or Siege of Yorktown was fought from April 5 to May 4, 1862, as part of the Peninsula Campaign

Peninsula Campaign

The Peninsula Campaign of the American Civil War was a major Union operation launched in southeastern Virginia from March through July 1862, the first large-scale offensive in the Eastern Theater. The operation, commanded by Maj. Gen. George B...

 of the American Civil War

American Civil War

The American Civil War was a civil war fought in the United States of America. In response to the election of Abraham Lincoln as President of the United States, 11 southern slave states declared their secession from the United States and formed the Confederate States of America ; the other 25...

. Marching from Fort Monroe

Fort Monroe

Fort Monroe was a military installation in Hampton, Virginia—at Old Point Comfort, the southern tip of the Virginia Peninsula...

, Union

Union Army

The Union Army was the land force that fought for the Union during the American Civil War. It was also known as the Federal Army, the U.S. Army, the Northern Army and the National Army...

  Maj. Gen.

Major general (United States)

In the United States Army, United States Marine Corps, and United States Air Force, major general is a two-star general-officer rank, with the pay grade of O-8. Major general ranks above brigadier general and below lieutenant general...

 George B. McClellan

George B. McClellan

George Brinton McClellan was a major general during the American Civil War. He organized the famous Army of the Potomac and served briefly as the general-in-chief of the Union Army. Early in the war, McClellan played an important role in raising a well-trained and organized army for the Union...

's Army of the Potomac

Army of the Potomac

The Army of the Potomac was the major Union Army in the Eastern Theater of the American Civil War.-History:The Army of the Potomac was created in 1861, but was then only the size of a corps . Its nucleus was called the Army of Northeastern Virginia, under Brig. Gen...

 encountered Maj. Gen. John B. Magruder

John B. Magruder

John Bankhead Magruder was a career military officer who served in the armies of three nations. He was a U.S. Army officer in the Mexican-American War, a Confederate general during the American Civil War, and a postbellum general in the Imperial Mexican Army...

's small Confederate

Confederate States Army

The Confederate States Army was the army of the Confederate States of America while the Confederacy existed during the American Civil War. On February 8, 1861, delegates from the seven Deep South states which had already declared their secession from the United States of America adopted the...

 force at Yorktown

Yorktown, Virginia

Yorktown is a census-designated place in York County, Virginia, United States. The population was 220 in the 2000 census. It is the county seat of York County, one of the eight original shires formed in colonial Virginia in 1634....

 behind the Warwick Line

Warwick Line

The Warwick Line was a defensive works across the Virginia Peninsula maintained along the Warwick River by Confederate General John B. Magruder against much larger Union forces under General George B...

. McClellan suspended his march up the Peninsula toward Richmond

Richmond, Virginia

Richmond is the capital of the Commonwealth of Virginia, in the United States. It is an independent city and not part of any county. Richmond is the center of the Richmond Metropolitan Statistical Area and the Greater Richmond area...

 and settled in for siege operations.

On April 5, the IV Corps of Brig. Gen.

Brigadier general (United States)

A brigadier general in the United States Army, Air Force, and Marine Corps, is a one-star general officer, with the pay grade of O-7. Brigadier general ranks above a colonel and below major general. Brigadier general is equivalent to the rank of rear admiral in the other uniformed...

 Erasmus D. Keyes

Erasmus D. Keyes

Erasmus Darwin Keyes was a businessman, banker, and military general, noted for leading the IV Corps of the Union Army of the Potomac during the first half of the American Civil War.-Early life and career:...

 made initial contact with Confederate defensive works at Lee's Mill, an area McClellan expected to move through without resistance.