The Raab Collection in Philadelphia is selling the document, which for decades has belonged to an anonymous private collector. The asking price is $100,000.
Lincoln wrote the letter to Maj. Gen. George B. McClellan on Oct. 29, 1862, requesting a progress report. The handwritten note on presidential stationery with "Executive Mansion" printed at the top, states that Lincoln was pleased with the movement of McClellan's Army of the Potomac as it crossed the Potomac River into Loudoun County, Va., and he was closely following its advancement.
The president's battlefield dispatch to McClellan ends: "When you get entirely across the river let me know. What do you know of the enemy?" The letter is signed A. Lincoln.
Though the apparently hastily scrawled note belies Lincoln's dissatisfaction with McClellan's performance, it is the president's final correspondence to the general before relieving him of his command for failing to aggressively pursue Confederate Gen. Robert E. Lee since the Battle of Antietam a month earlier.
"This was the last straw for Lincoln, who now came into his own," said Nathan Raab, vice president of The Raab Collection. "He realized that his strategic sense was better than that of his military experts and that he must exert leadership in military matters rather than defer to his generals."
Lincoln's demotion of McClellan on Nov. 5, 1862, was the first of a series of decisions that culminated with the president naming Ulysses S. Grant as his commanding general, a move that ultimately ended the war and brought victory to the North in April 1865. Lincoln was assassinated days afterward.
Four years later, Grant became the 18th president of the United States.
