G is for Gettysburg
Gettysburg was the blodiest three days in the Civil War. It was also a major turning point for the Army of the Potomac.
H is for Herman Haupt
Herman Haupt was a Union General who greatly revolutionized the movement of troops and supplies via the railroad system.
I is for Insurrection
John Brown attempted to start an insurrection among the slaves but, his plans were foiled by the U.S. Army.