Advance elements of the Federal and Confederate armies clash in southern Pennsylvania, beginning what would grow into the most terrible battle in American history.

Exploring the most important 55 months in American history
Advance elements of the Federal and Confederate armies clash in southern Pennsylvania, beginning what would grow into the most terrible battle in American history.
Robert E. Lee submits a request to President Jefferson Davis to reorganize his Confederate army before launching his second northern invasion.
Three Confederate forces converge on the Federal garrison at Harpers Ferry, at the strategic confluence of the Potomac and Shenandoah rivers.
Thomas “Stonewall” Jackson’s Confederates advance toward Culpeper Court House and confront a Federal force deployed to stop them at Cedar Mountain in northern Virginia.
John Pope sends his Federal army probing southward from northern Virginia, while Robert E. Lee determines that Pope is the main threat to his Confederate army.
Robert E. Lee makes another attempt to destroy the Federal Army of the Potomac on the Virginia Peninsula, this time attacking at Glendale, Frayser’s Farm, and White Oak Swamp.