...raight line running due east from the Potomac and passing through Sharpsburg would cross the Antietam river about 1 1/2 miles from the town. The general direction of the Antietam in front (east) of Sharpsburg is a little west of south. And this, too, is the general direction of the Potomac in the vicinity of the battlefield. About 3 miles below Sharpsburg the Potomac makes a sweeping bend to the east ...