A remarkable plan to save the Federal army under siege in Chattanooga is set in motion.

Exploring the most important 55 months in American history
A remarkable plan to save the Federal army under siege in Chattanooga is set in motion.
President Abraham Lincoln accepts Joseph Hooker’s resignation as Army of the Potomac commander, daringly replacing an army commander during an enemy invasion.
Robert E. Lee warns his Confederates against pillaging in Pennsylvania, while Joseph Hooker makes another request to take over the Federal garrisons in the Shenandoah Valley.
Most of the Federal Army of the Potomac enters Maryland, Joseph Hooker asks to take command of the garrisons in the Shenandoah, and the Confederate invasion of Pennsylvania spreads panic.
The last troops of the Confederate Army of Northern Virginia cross the Potomac River into Maryland, while the first troops of the Federal Army of the Potomac begin crossing as well.
Joseph Hooker pinpoints the location of the Confederate Army of Northern Virginia as it moves through Maryland and Pennsylvania, and issues orders for his Federal army to cross the Potomac in pursuit.