The Peninsula (or Peninsular) Campaign was a major Union offensive against the Confederate capital of Richmond led by Major General George B. McClellan in the spring and summer of 1862, during the American Civil War. After moving his Army of the Potomac by boat to Fort Monroe on the Atlantic coast in late April, McClellan planned an advance toward Richmond via the peninsula formed by the York and James Rivers. Due to a habit of consistently overestimating his enemy’s numbers, the Union general refused to act until late May. The first stage of the Peninsula Campaign ended in the inconclusive Battle of Seven Pines, during which Confederate General Joseph Johnston was injured and command passed to Robert E. Lee. Beginning on June 25, Lee’s Army of Northern Virginia held off the Army of the Potomac in a series of engagements known as the Seven Days’ Battles, effectively ending McClellan’s campaign toward Richmond.