1861    American Civil War: Robert E. Lee resigns his commission in the United States Army in order to command the forces of the state of Virginia.

1862    Civil War Maryland Campaign: General Robert E. Lee takes the Army of Northern Virginia, and the war, into the North.

1862    American Civil War: Union soldiers find a copy of Robert E. Lee's battle plans in a field outside Frederick, Maryland. It is the prelude to the Battle of Antietam.

1862    American Civil War: George B. McClellan halts the northward drive of Robert E. Lee's Confederate army in the single-day Battle of Antietam, the bloodiest day in American history.

1862    American Civil War: At the Battle of Fredericksburg, Confederate General Robert E. Lee defeats the Union Major General Ambrose E. Burnside.

1863    American Civil War: following his defeat in the Battle of Gettysburg, General Robert E. Lee sends a letter of resignation to Confederate President Jefferson Davis (which is refused upon receipt).

1864    Arlington National Cemetery is established when {{convert|200|acre|km²}} around Arlington Mansion (formerly owned by Confederate General Robert E. Lee) are officially set aside as a military cemetery by U.S. Secretary of War Edwin M. Stanton.

1865    American Civil War: The Siege of Petersburg is broken – Union troops capture the trenches around Petersburg, Virginia, forcing Confederate General Robert E. Lee to retreat.

1865    American Civil War: Robert E. Lee surrenders the Army of Northern Virginia (26,765 troops) to Ulysses S. Grant at Appomattox Courthouse, Virginia, effectively ending the war.

1865    American Civil War: A day after his surrender to Union forces, Confederate General Robert E. Lee addresses his troops for the last time.