From the Associated Press:
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.